Product Specifications
2011-2021 Subaru WRX STI 2.5L Turbo Sedan 4-Door Cat-Back Exhaust System
This direct bolt-on cat-back exhaust is made for the 2011-2021 Subaru WRX STI 4-door sedan — the GV-chassis model with the factory 2.5L EJ257 turbocharged Boxer-4. It replaces the piping from the rear of the catalytic converter to the tailpipe and is available in T-304 or 201 stainless steel, so you can match the material to your climate and budget. Verify your exact model in the fitment section below before ordering: this kit is sedan-specific and does not fit the hatchback or the non-STI WRX.
Built on a 3-inch mandrel-bent layout with TIG-welded joints and 10 mm CNC-machined flanges, the system ships with two main pipes, a silencer tail pipe, and the gaskets, clamps, and hardware needed to join them. Both material options share the same pipe layout and included parts, so the only decision between the two variants is the stainless grade.
Specifications
Applies to both material variants (T-304 and 201 stainless steel).
| Component | Material | Thickness (mm) | Notes |
|---|---|---|---|
| Bend Pipes | 304 / 201 Stainless Steel | 1.23 – 1.25 | Two material options available |
| Inner Perforated Tube (Muffler) | 409 Stainless Steel | 0.95 – 0.97 | Located inside the muffler body |
| Perforated Tube End Cap | 304 Stainless Steel | 0.87 | Cap the inner mesh tube |
| Flanges | 304 / 201 Stainless Steel | 10 | Laser-cut for precise fit |
Key Features
- Converter-Back System Scope: This kit replaces the exhaust section from the rear of the catalytic converter to the tailpipe, leaving the factory catalytic converter and O2 sensors in their original positions — a mid-to-rear upgrade rather than a full exhaust replacement.
- 3-Inch Mandrel-Bent Main Piping: The main pipes run at 3 inches in diameter with mandrel bends and 1.23–1.25 mm stainless walls, so the system keeps one uniform pipe path — the figure to match if you plan to pair it with other 3-inch exhaust sections.
- Two Stainless Grades, Same Layout: The identical pipe layout and included hardware are offered in T-304 or 201 stainless. T-304 gives higher corrosion resistance for wet or salt-treated regions; 201 is the budget-minded grade for milder climates — pick by environment first, then budget.
- TIG-Welded Joints with 10 mm CNC Flanges: Joints are TIG-welded and the flanges are 10 mm laser-cut, CNC-machined pieces that the gaskets, clamps, and factory mounting points bolt to.
- Perforated-Core Muffler Structure: Inside the muffler body, exhaust passes through a 409 stainless perforated inner tube capped with a 304 stainless end cap — the internal silencing structure of the system as listed in the specifications table.
- Hardware Kit Included: Gaskets, clamps, and mounting hardware ship with the pipes, so the included sections can be joined with standard hand tools and no extra parts for the kit itself.
Care tip — if your kit ships with the heat-treated blue tips, the colored surface is a finish layer and not a coating. Clean only with water (and a small amount of mild soap if needed) and never use abrasive pads or rubbing compounds, otherwise the blue color will be removed and that type of surface wear is not covered.
What's In The Box?
- 1 × Silencer Tail Pipe
- 2 × Main Pipe A
- 1 × Gaskets, Clamps, and Hardware Kit
Exhaust System vs. Cat-Back Exhaust
The exhaust system is the full assembly that routes gases from the engine to the tailpipe — exhaust manifolds, catalytic converters, resonators, mufflers, and exhaust tips — and it handles emissions control, noise reduction, and gas expulsion together.
A cat-back exhaust covers only the section from the rear of the catalytic converter to the tailpipe, excluding the converter itself. If you want to change the mid and rear piping while keeping the catalytic section as it is, a cat-back is the part of the system that matches that scope. If you intend to also change the downpipe, headers, or converter, a full exhaust replacement is the broader option — confirm which parts you plan to modify before ordering.
Check Before Ordering
- Confirm your vehicle: 2011-2021 Subaru WRX STI 4-door sedan, GV chassis, factory 2.5L EJ257 turbocharged Boxer-4 — check the model year and body style on your registration or VIN plate.
- Does not fit: WRX hatchback (5-door), 2008-2010 WRX STI (pre-GV), standard 2.0L WRX, and any non-sedan configuration. This kit is not interchangeable across those body styles.
- Modified or damaged exhaust: If the existing piping, hangers, or flanges were replaced, repaired after an accident, or altered from factory, confirm the mounting condition with our support team before you order.
- Blue tip care: The heat-treated blue tips must be cleaned with water only and, if absolutely necessary, a very gentle soap. Never scrub or use rubbing compounds or chemical cleaners — aggressive cleaning removes the heat-treated color and voids the finish warranty.
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.
Looking for more exhaust options? Browse our complete Exhaust System collection, the dedicated Cat-Back Exhaust category, or the Subaru Cat-Back Exhaust lineup. For complete upgrade packages, see our Exhaust System Kits. Limited-time offer: save on the entire Subaru exhaust lineup during our Labor Day Sale.
