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Upgrading your Scion xB cat-back exhaust system can noticeably change how the car breathes and sounds. The right system affects throttle response, exhaust note, and long-term durability, so choosing carefully matters whether you want a subtle refinement or a more aggressive tone. This guide highlights the top six shortlisted options for the Scion xB, chosen for their materials, construction, and fitment ease. We evaluated each candidate for build quality and installation complexity, then ranked the finalists. Read on to see which systems made the list and what to expect during installation.
Looking for other parts? See all Scion xB parts & accessories.
Top Picks at a Glance
| Best Reviewed A top-rated pick with lots of positive feedback | MBRP S5326AL 2.5" Cat-Back Single-Side Exhaust System (Aluminized Steel) |  |
| Best Quality Built to a higher standard if you want something more solid | Borla Cat-Back Performance Exhaust System (140334) for 2009–2017 Mitsubishi Lancer Ralliart |  |
| Best Budget The cheapest option that still gets the job done reliably | Rev9 FlowMaxx Stainless Steel Cat-Back Exhaust for Subaru WRX (VB) |  |
| Most Sold A high-volume bestseller chosen again and again | MBRP Black Series 3" Dual Split Rear Cat-Back Exhaust System with 4.5" Tips |  |
| Best Value for Money The sweet spot between price and what you get | Borla Cat-Back Performance Exhaust System 14411 |  |
| Best Overall The best all-around choice for most situations | Invidia N1 Cat-Back Exhaust System with Stainless Steel Tip for Scion FR-S / Subaru BR-Z |  |
1. MBRP S5326AL 2.5" Cat-Back Single-Side Exhaust System (Aluminized Steel)
| Installation Type | Bolt-On |
|---|---|
| Finish Type | ALUMINIZED |
| Manufacturer | MBRP |
| OEM Part Number | S5326AL |
This MBRP cat-back replaces the factory rear exhaust with mandrel-bent 2.5-inch tubing and a single-side aluminized muffler assembly intended to increase exhaust flow and produce a deeper, more assertive tone. It installs as a bolt-on with matching hangers and clamps, so a competent DIYer can fit it using basic tools though some models may require trimming the straight pipe for proper fit. Mandrel bends keep the tubing free of ripples to preserve flow and durability from the aluminized finish helps resist corrosion compared with plain mild steel. Real-world benefits include a fuller low-end sound, reduced backpressure that can make throttle response feel crisper, and straightforward installation without welding. Limitations are that the part is offered in a long-bed configuration so shorter beds or different vehicle platforms may require cutting and adjustment, and it does not include an exhaust flange gasket in every kit so you may need to source that separately. Sound preference is subjective and some drivers report low-speed drone in certain setups.
Best for: A reliability-focused buyer who prioritizes a durable, factory-replacement style upgrade and easy bolt-on installation to keep maintenance simple and predictable.
Less Ideal for: Buyers seeking a Scion xB-specific fit or expecting a plug-and-play long-bed truck part to fit without modification should consider alternatives designed for their vehicle or plan on modification and extra parts.
- Mandrel-bent 2.5" tubing maintains smooth internal flow for better exhaust scavenging
- Aluminized finish improves corrosion resistance versus untreated steel
- Bolt-on design with matched hangers allows largely straightforward installation
- Produces a deeper, more aggressive exhaust note and improved throttle response
- Kit is sized for long-bed trucks and may require cutting or modification for other bed lengths or platforms
- Does not reliably include the exhaust flange gasket so an extra part may be needed
Verdict A durable, mandrel-bent aluminized cat-back that gives a fuller sound and easier installation but may need trimming and extra parts for non-long-bed or different-vehicle fitment.
2. Borla Cat-Back Performance Exhaust System (140334) for 2009–2017 Mitsubishi Lancer Ralliart
| Fitment years | 2009-2017 Lancer Ralliart |
|---|---|
| Material | T-304 Stainless Steel |
| Installation | Bolt on, uses factory hangers |
| Manufacturer warranty | Million-Mile Warranty |
This Borla cat-back replaces the factory rear exhaust on the listed 2009–2017 Lancer Ralliart and is designed to free up exhaust flow with straight-through, multi-core internals and mandrel bends. In typical use it bolts on to the existing midpipe flange and hangs from factory rubber isolators, so installation is usually quick for anyone with basic tools or shop access. The T-304 stainless construction and precision CNC manufacturing mean it resists corrosion and keeps fitment consistent, while the Borla tune produces a deep, aggressive idle and strong exhaust note under acceleration that many drivers describe as sporty rather than buzzy. Practical benefits include potential small gains in throttle response and a durable, maintenance-light system backed by long-term support. Limitations to consider are the fixed 2.5 inch flange size which can prevent direct connection to larger aftermarket midpipes without modification, and some users report clamp-area leaks that may require welding or careful sealing for a perfect fit. Expect a performance-oriented sound and reliable materials at the cost of compatibility with certain upgraded midpipe setups.
Best for: Performance-oriented buyers who prioritize factory-quality hardware and a deeper, aggressive exhaust note to match spirited driving and track-influenced street use.
Less Ideal for: Buyers planning major exhaust upgrades that require a larger midpipe flange or users looking for a fully modular system designed for frequent swapping and stage upgrades.
- T-304 stainless steel construction for long-term corrosion resistance
- Straight-through, multi-core internal design aimed at improving exhaust flow
- Mandrel bends and CNC manufacturing for consistent fit and minimal flow restrictions
- Bolt-on installation that uses factory hangers for relatively quick fitting
- 2.5 inch flange limits direct compatibility with larger aftermarket midpipes
- Some customers report clamp area leaks that may require welding or rework
Verdict A high-quality, durable cat-back that delivers a deep, aggressive sound and reliable fitment for performance-minded drivers, but it may need modification to pair with larger aftermarket midpipes.
3. Rev9 FlowMaxx Stainless Steel Cat-Back Exhaust for Subaru WRX (VB)
| Installation Type | Bolt-On |
|---|---|
| Compatible with Vehicle Type | Car |
| Tip Description | Double Wall Round Slant Cut |
| Material Type | Stainless Steel |
This Rev9 FlowMaxx cat-back replaces the factory rear exhaust on the Subaru WRX (VB) and is built from polished stainless steel with mandrel-bent piping and double-wall 3.5-inch tips. It is a direct-fit bolt-on system intended to install downstream of the catalytic converter, so it does not alter emission control hardware. Typical installation uses stock hanger locations and flange connections, and most buyers report straightforward assembly with basic tools. In use the system sharpens throttle response slightly and produces a deeper, modestly louder exhaust note that is most noticeable at cold start and under acceleration. Practical benefits include improved exhaust flow, a more muscular tone without being overly aggressive, and corrosion resistance from stainless construction. Limitations are that the supplied hardware may be undersized for some installations and some minor adjustment is typically needed to center the tips in the bumper cutouts; sound increase is moderate rather than dramatic. Backed by a one-year manufacturer limited warranty.
Best for: Budget-conscious drivers who want a noticeable but restrained sound and improved exhaust flow without expensive tuning or major modifications.
Less Ideal for: Drivers seeking an aggressive, race-level tone or those who need a fully bolt-on system with heavier-duty supplied hardware should consider other, more performance-focused options.
- Mandrel-bent stainless steel piping for smoother exhaust flow and durability
- Direct bolt-on fitment designed to use factory hanger locations for simpler installation
- Double-wall 3.5-inch polished tips that give a deeper, refined exhaust tone
- Installs downstream of the catalytic converter so it does not modify emission control hardware
- Supplied bolts and hardware may be undersized, requiring replacement during installation
- Sound increase is moderate and may disappoint buyers seeking a loud, aggressive tone
Verdict A wallet-friendly stainless cat-back that gives the WRX a deeper, refined tone and better flow while staying conservative on volume.
4. MBRP Black Series 3" Dual Split Rear Cat-Back Exhaust System with 4.5" Tips
| Brand | MBRP |
|---|---|
| Item model number | S7274BLK |
| Tip diameter | 4.5" |
| Pipe diameter | 3" |
This MBRP Black Series cat-back is a direct-fit performance exhaust intended to replace the factory system on compatible vehicles. It uses 3 inch mandrel-bent piping, a vehicle-specific muffler design, and a black heat-resistant coating to improve exhaust flow, lower exhaust temperatures, and give a deeper, muscle-style tone without being excessively loud. The system ships complete with clamps and hangers for a bolt-on installation to factory hangers, which typically makes it a one to two hour job for a competent installer. The black coating and sealed seams aim to resist rust and hold up under heat, and the stamped logo and 4.5 inch tips add a finished look. Limitations to consider are reported occasional shipping damage and that sound increase is more of a deeper tone than extreme volume, so buyers seeking aggressive race-level noise or a stainless steel finish may prefer different options. Professional installation is recommended and local emissions rules should be checked before fitting.
Best for: Risk-averse mainstream buyers who prioritize a reliable, direct-fit upgrade that improves sound and drivetrain efficiency without radical modifications.
Less Ideal for: Drivers who want the loudest, race-level exhaust or those who insist on an uncoated stainless steel finish for maximum longevity should consider alternatives.
- Direct-fit bolt-on design with included clamps and hangers for straightforward installation
- Mandrel-bent 3" tubing and tuned muffler design to improve flow and deliver a deeper, muscle-style exhaust note
- Black heat-resistant coating and sealed seams for improved corrosion resistance and durability
- Comes with stamped logo tips for a finished, factory-style appearance
- Reported instances of shipping damage to pipes or tips on some units
- Black coated finish is not stainless steel and may show wear differently over long term
Verdict A straightforward, bolt-on cat-back that deepens sound and improves flow while prioritizing a corrosion-resistant coated finish for practical, risk-averse buyers.
5. Borla Cat-Back Performance Exhaust System 14411
| Material | T-304 stainless steel |
|---|---|
| Fitment type | Cat-back performance exhaust |
| Installation | Bolt on |
| Construction | All welded |
This Borla cat-back replaces the factory rear exhaust with a mandrel-bent stainless steel system intended to improve flow, responsiveness, and sound. It installs as a bolt-on unit and is typically used to add a deeper, throaty note and slight power and torque gains without major engine work. Notable features include T-304 stainless-steel construction, all-welded assemblies for durability, and the signature Borla sound profile that many owners describe as a deep growl at higher RPMs. In real-world use you can expect easier revving and a richer exhaust tone under throttle while keeping highway drone low in many setups. Limitations are cost and that sound level is subjective—some users find it only modestly louder than stock while others report it is quite aggressive; fitment and final tone also depend on piping diameter and the vehicle's intake and tuning. Installation is straightforward for a shop or experienced DIYer, but sealing clamps and hanger alignment should be checked to avoid leaks.
Best for: A practical optimizer seeking a durable, factory-quality exhaust that sharpens throttle response and adds a richer sound while prioritizing long-term value and a professional fitment.
Less Ideal for: Buyers who want the loudest possible system or large measured horsepower gains without extra engine modifications should consider more extreme or turbo-specific options instead.
- T-304 stainless steel construction for long-term corrosion resistance
- Bolt-on, all-welded design that simplifies installation and maintains alignment
- Distinctive deep, throaty exhaust note under load favored by performance drivers
- Mandrel-bent piping improves exhaust flow compared with restrictive stock tubing
- Not guaranteed to produce a large horsepower gain without additional tuning or supporting modifications
- Sound is subjective and may be only moderately louder than stock on some vehicles
Verdict A durable, bolt-on performance cat-back that delivers a refined, sporty sound and improved flow for owners who want a long-lasting, factory-quality upgrade rather than maximum loudness or big power gains.
6. Invidia N1 Cat-Back Exhaust System with Stainless Steel Tip for Scion FR-S / Subaru BR-Z
| Material Type | Stainless Steel |
|---|---|
| Installation Type | Bolt-On |
| Compatible with Vehicle Type | Car |
The Invidia N1 cat-back replaces the factory rear exhaust with mandrel-bent stainless steel piping, CNC-machined flanges, and a polished stainless tip to improve flow and produce a stronger, deeper sound. It installs as a bolt-on system and is typically used by owners who want a noticeable increase in mid-to-top end power and a richer exhaust note without major engine changes. Notable features include SUS304 construction for corrosion resistance and mandrel bends that reduce restriction for better horsepower and torque at higher RPM. Real-world benefits include a fuller, sportier tone, an expected uptick in throttle response at higher revs, and durable materials that hold up to everyday driving. Downsides are increased cabin drone for some drivers and the louder tone that may be too aggressive for quiet daily commuting; there are quieter end pieces included but tuning sound preference may require additional accessories or adjustment. Fitment and installation are straightforward on the Scion FR-S platform when following vehicle-specific procedures.
Best for: Balanced owners who want a reliable, performance-oriented upgrade that improves sound and high‑RPM power while keeping installation simple and predictable.
Less Ideal for: Drivers who prioritize a near-silent daily commute or strict compliance with low-noise restrictions should consider a quieter aftermarket option or modified mufflers instead.
- Mandrel-bent SUS304 stainless piping for improved exhaust flow and corrosion resistance
- CNC-machined flanges for solid sealing and simpler bolt-on installation
- Polished stainless tip and finish for a durable, factory-quality appearance
- Produces stronger mid-to-top end power and a deeper, sporty exhaust note
- Can produce noticeable drone or louder cabin noise at cruising speeds for some drivers
- May be louder than preferred for strict noise-sensitive areas despite included quieter end pieces
Verdict A durable, bolt-on performance cat-back that gives Scion FR-S owners a richer sound and improved high‑RPM flow but may be too loud for noise-sensitive daily driving.
Choosing the Right Scion xB Cat-back Exhaust System: Key Factors to Consider
Material and Corrosion Resistance
Material choice affects longevity and how the exhaust weathers road salt and moisture. Stainless steel alloys resist corrosion longer than mild steel and often carry warranties. Thicker wall tubing is less prone to rust-through and can stand up to repeated heat cycles without warping.
Finish treatments like ceramic coating or high-temperature paint add protection and can reduce underbody heat transfer. When comparing options, check for stated alloy grades and weld quality. Corrosion resistance matters because replacement or repair of exhaust sections is more time-consuming than choosing a higher-quality initial unit.
Flow Design and Pipe Diameter
The tubing diameter and internal flow path determine backpressure and how the engine delivers torque across the rev range. Too-small diameters can create restriction and negatively affect midrange performance, while overly large diameters may reduce low-end response.
Look for systems that match the engine's characteristics with a balanced diameter and smooth bends. Mandrel-bent tubing maintains cross-section through curves, helping preserve flow. Proper flow design ensures the upgrade enhances performance without compromising drivability.
Fitment and Installation Effort
A donor system that aligns with factory hangers and flanges reduces installation time and the need for custom fabrication. Bolt-on systems that include required gaskets and hardware simplify the process. Understand whether the system is a direct-fit cat-back for the Scion xB or intended as a universal unit that requires modification.
Consider access to tools and whether lifting equipment is needed. Installation difficulty affects total ownership cost because professional labor can be significant. If you plan to install yourself, prioritize kits with comprehensive instructions and clear fitment notes for the Scion xB.
Muffler Design and Acoustic Characteristics
Muffler internals and resonator placement shape the exhaust tone and interior drone levels. Chambered, straight-through, and turbo-style mufflers each produce distinct sound signatures and may emphasize different frequency ranges.
Think about how often you drive at highway speeds and what cabin noise you find acceptable. A system tuned for aggressive sound may add drone under steady throttle, while a more refined design balances performance gains with comfortable in-cabin noise. Matching muffler design to your daily use is key.
Hanger and Mounting Hardware Quality
Secure hanger points and robust mounting hardware prevent rattles and misalignment over time. Poorly designed hangers can lead to stress at welds and premature fatigue. Look for systems that provide reinforced hangers, isolation bushings, or improved mounting brackets when applicable.
Good hardware also simplifies installation and reduces the chance of leaks at flange connections. Consider whether replacement of rubber isolators or hangers is recommended during installation to ensure a lasting fit.
Compatibility With Modifications
If you plan other modifications like an upgraded catalytic converter, header, or intake, ensure the cat-back system integrates with those changes. Matching inlet and outlet diameters and flange types avoids additional adapters or fabrication.
Some systems are more tolerant of upstream changes, while others expect stock geometry. Planning compatibility ahead prevents costly rework and helps maintain the intended flow and sound characteristics after other upgrades.
FAQ
Will a cat-back exhaust change the Scion xB engine performance?
A cat-back exhaust can slightly alter performance by reducing backpressure and improving exhaust flow. Gains are usually modest on naturally aspirated engines and depend on pipe sizing, muffler design, and overall system tuning. Significant performance changes often require complementary upgrades or ECU tuning.
How difficult is catback exhaust installation on a Scion xB?
Difficulty varies by system. Direct-fit cat-back units that align with factory hangers are generally straightforward for someone with basic tools and a jack or lift. Universal systems or those needing adapter flanges can require cutting, welding, or fabrication and are better handled by a shop.
Will changing to an aftermarket cat-back increase cabin drone?
It often depends on muffler design and resonator placement. Some aftermarket systems can introduce drone at certain steady RPMs, while others use internal baffling or resonators to minimize cabin resonance. Choosing a design that balances note and daily comfort helps reduce unwanted drone.
Is stainless steel necessary for a cat-back system?
Stainless steel offers better corrosion resistance and often longer service life than mild steel, especially in climates with road salt or frequent moisture. However, quality coatings and proper maintenance can extend the life of other materials. Consider expected use and local conditions when prioritizing material.
Do I need to retune the engine after installing a cat-back?
Most cat-back installations do not require an immediate tune for basic fitment and reliability. However, if the new system significantly alters flow characteristics or is combined with other performance upgrades, a tune can help optimize air/fuel ratios and unlock any potential gains.
How We Chose the Best Scion xB Cat-back Exhaust System
We focused on attributes that matter most for Scion xB cat-back exhaust system upgrades. Primary evaluation criteria included material and corrosion resistance, overall flow design and backpressure characteristics, installation complexity and required tools, and exhaust note quality. We also considered hanger and flange fitment, inlet and outlet diameters, and whether hardware and gaskets were included for direct fitment. Our testing and selection favored systems built from durable materials and with clear fitment instructions for the Scion xB platform. Units requiring extensive fabrication, major cutting of factory components, or unsupported fitment were excluded. We also deprioritized designs with ambiguous inlet/outlet sizing or poor hanger alignment. The final list balances longevity, sonic character, and realistic installation effort for owners who want a reliable upgrade without unpredictable modification work.
Our full evaluation process is outlined in our review methodology.
Conclusion
Choosing the right Scion xB cat-back exhaust system means balancing material durability, acoustic goals, and installation practicality. Prioritize systems with proven corrosion resistance, appropriate pipe sizing, and muffler designs that match how you drive. Keep in mind the tradeoffs between sound and cabin comfort, and consider fitment notes to avoid extensive fabrication. Planning for compatibility with any other performance upgrades will help ensure the system performs as expected and lasts over time.
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