Choose the Exhaust Section That Matches Your Build
This 2015–2021 Subaru WRX and WRX STI exhaust family gives you two different upgrade paths: an axle-back configuration for the rear section, or a cat-back configuration that replaces more of the downstream exhaust. Select by SKU before ordering because pipe size, tip size, resonator layout, muffler layout, finish, and package contents are not the same across the four options.
Start with product type: Choose FLES08144 only when you need the axle-back configuration. Choose FLES08141, FLES08142, or FLES08143 when you need a cat-back configuration.
Match the vehicle: This product family is listed for 2015–2021 Subaru WRX and WRX STI AWD four-door applications. Match the model, engine, and selected SKU before ordering.
Match the hardware: Package contents differ by SKU. Review the included-hardware row before installation.
Account for an existing exhaust setup: A non-factory downpipe, intermediate connection, or other exhaust modification can change interface requirements and final alignment. Contact customer support if your vehicle is not using the factory connection layout.
Specifications
| SKU / Option | Product type | Pipe diameter | Tips / Exit | Muffler / Resonator | Material / Tip finish |
|---|---|---|---|---|---|
|
FLES08144 Axle Back Burnt Tips |
Axle-back | 2.36 in OD | Four 3.5 in tips Dual rear exit |
No muffler No resonator |
201 stainless steel Burnt tips |
|
FLES08142 Polished Catback |
Cat-back | 3 in + 2.36 in OD | Four 4 in tips Dual rear exit |
No muffler One resonator |
201 stainless steel Polished tips |
|
FLES08143 Burnt Catback |
Cat-back | 2.36 in OD | Four 4 in tips Dual rear exit |
No muffler No resonator |
201 stainless steel Burnt tips |
|
FLES08141 Burnt Catback w/ Muffler |
Cat-back | 3 in + 2.36 in OD | Four 4 in tips Dual rear exit |
Four mufflers One resonator |
201 stainless steel Burnt tips |
Included Hardware
- FLES08144: Gaskets, bolts, and nuts.
- FLES08141, FLES08142, and FLES08143: Gaskets, bolts, nuts, and clamps.
Package contents vary by selected configuration. Select the required SKU before ordering, compare the received parts with the selected configuration, and contact customer support before installation if parts do not match.
Where Each Option Sits in the Exhaust System
The axle-back option changes the rear section and is not a full cat-back exhaust. The cat-back options replace a larger downstream section and use different pipe, resonator, and muffler layouts. None of these options should be selected as a header, downpipe, catalytic converter, or test-pipe replacement.
How to Choose
- Choose axle-back or cat-back based on the section you intend to replace.
- Match the SKU to the required muffler and resonator layout.
- Match the 3.5-inch or 4-inch tip size and burnt or polished finish.
- Review the included hardware for that SKU.
- Check the vehicle and existing exhaust connection before installation.
Sound & Cabin Resonance
Muffler and resonator layouts differ across the four configurations, so one sound description cannot represent every SKU. Final volume, tone, and cabin resonance also depend on the engine, transmission, cruising speed and RPM, and other exhaust modifications. Choose by confirmed hardware layout rather than a universal loudness label.
Drivers who need a specific cold-start level, highway-cruise result, or drone threshold should review a sound sample recorded on the same vehicle and exhaust configuration before choosing a SKU.
Installation & Post-Installation Checks
These configurations are listed as bolt-on installations with no cutting. Before starting, match the SKU, pipe layout, gaskets, fasteners, clamps, and vehicle connection. An altered exhaust connection can require a different installation plan.
- Support the exhaust before loosening the factory hardware.
- Position the full system before final tightening so the hangers and tips can be aligned without preload.
- After installation, check every joint for leaks.
- Check clearance around the body, heat shields, suspension, and rear bumper.
- Check hanger position, tip alignment, and bumper clearance.
- Stop driving and inspect the installation if there is contact, knocking, abnormal vibration, overheating, an unexplained warning light, or an exhaust leak.
Emissions, Road Use & Vehicle Warranty
Do not remove, bypass, or relocate a catalytic converter, oxygen sensor, or other emissions-control component during installation. Road-use, inspection, and noise requirements vary by state and locality. Product coverage and a vehicle manufacturer's warranty are separate matters; warranty decisions can depend on the cause of a specific failure.
Who Should Not Buy
- Do not order if your vehicle is outside the listed 2015–2021 WRX or WRX STI applications.
- Do not order the axle-back SKU when you need a full cat-back configuration.
- Do not order a cat-back SKU when you only intend to replace the rear axle-back section.
- Do not order by sound label alone when you require a measured cold-start, cruise, or cabin-resonance result.
- Do not proceed with installation if the selected parts do not match the vehicle connection or the SKU package.
Shipping & Returns
Free U.S. Shipping: Orders are typically processed within 1–2 business days and delivered within 7–9 business days. Additional charges may apply to remote areas.
30-Day Returns: Unopened and unused items in their original packaging may be returned within 30 days of receipt. Return shipping is covered for verified quality issues.
Worry-Free Delivery: Optional protection against eligible loss, theft, delay, or transit damage is available at checkout.
Fitment & Compatibility
- Fits factory-equipped vehicles with listed configurations.
- Please confirm vehicle specifications before ordering.
| YEAR | MAKE | MODEL | ENGINE | DRIVE / BODY |
|---|---|---|---|---|
| 2015-2021 | Subaru | WRX | 2.0L H4 | AWD — 4 Door |
| 2.5L H4 | AWD — 4 Door | |||
| 2015-2021 | Subaru | WRX STI | 2.5L H4 | AWD — 4 Door |
2015–2021 Subaru WRX & WRX STI Exhaust FAQs
Q1: Is every option on this listing a cat-back exhaust?
A1: No. FLES08144 is an axle-back configuration. FLES08141, FLES08142, and FLES08143 are cat-back configurations.
Q2: Which vehicles are listed for this exhaust family?
A2: The listed applications are 2015–2021 Subaru WRX 2.0L H4 AWD four-door models and 2015–2021 Subaru WRX STI 2.5L H4 AWD four-door models. Match the exact vehicle and selected SKU before ordering.
Q3: Will this fit a 2022, 2023, or 2024 WRX?
A3: Those model years are not included in the listed 2015–2021 applications. Do not order this configuration for a later model year without a matching application listing.
Q4: What is the difference between the axle-back and cat-back choices?
A4: The axle-back SKU replaces the rear section. The cat-back SKUs replace a larger downstream section and use different pipe, resonator, and muffler layouts.
Q5: What pipe and tip sizes are available?
A5: FLES08144 uses 2.36-inch OD piping with four 3.5-inch tips. FLES08143 uses 2.36-inch OD piping with four 4-inch tips. FLES08141 and FLES08142 list 3-inch plus 2.36-inch OD sections with four 4-inch tips.
Q6: Which SKU includes mufflers?
A6: FLES08141 includes four mufflers and one resonator. FLES08142 includes one resonator and no mufflers. FLES08143 and FLES08144 include neither mufflers nor a resonator.
Q7: What hardware is included?
A7: FLES08144 lists gaskets, bolts, and nuts. The three cat-back SKUs list gaskets, bolts, nuts, and clamps. Check the selected configuration before installation.
Q8: Does installation require cutting?
A8: The four configurations are listed as bolt-on installations with no cutting. Existing exhaust modifications can change the connection and installation requirements.
Q9: Which option is the quietest or has the least drone?
A9: The hardware layouts differ, but no single sound result applies to every vehicle and configuration. Use a sound sample from the same vehicle, SKU, cruising RPM, and supporting exhaust setup when cabin resonance is a deciding factor.
Q10: Will a cat-back exhaust add a specific amount of horsepower?
A10: No fixed horsepower or torque result should be assumed. Results depend on the vehicle, complete exhaust setup, engine calibration, and test conditions.
Q11: Does this listing include a downpipe or catalytic converter?
A11: These options are axle-back or cat-back configurations, not header, downpipe, catalytic-converter, or test-pipe replacements.
Q12: What should I check after installation?
A12: Check for leaks, contact with the body or heat shields, hanger preload, abnormal vibration, tip alignment, and bumper clearance. Stop driving and inspect the system if there is knocking, overheating, an unexplained warning light, or an exhaust leak.
Q13: Is this exhaust legal for street use everywhere?
A13: Road-use, inspection, and noise rules vary by state and locality. Installation must not remove, bypass, or relocate emissions-control components.
Q14: Will this exhaust automatically void my vehicle warranty?
A14: Product coverage and the vehicle manufacturer's warranty are separate. A warranty decision can depend on whether the installed part caused the specific failure being evaluated.