COBB Stainless Steel Catback Exhaust – 2015–2021 Subaru WRX / STI

The COBB Stainless Steel Cat-Back Exhaust for the 2015–2021 Subaru WRX and STI Sedan is built for drivers who want premium construction, proven performance, and a refined exhaust note without going over the top. Designed as a true vehicle-specific system, this cat-back delivers strong flow and excellent fitment while keeping a clean, stock-like appearance.

From the cast flanges to the bespoke muffler design, every section of this exhaust is engineered for durability, leak-free installation, and crisp sound quality. The result is an exhaust note that is noticeably more aggressive than stock without introducing unwanted cabin drone.

Key Features

• 304 Stainless Steel Construction: High-quality stainless steel throughout for excellent corrosion resistance and long-term durability.
• High Quality Cast Y-Split & Flanges: Improves strength, longevity, and sealing compared to welded split designs.
• TIG Welded: Clean, precise welds for strength and a premium finish.
• Adjustable Slip-Fit Tips: Allows for fine-tuning tip placement for the perfect fit.
• Refined Sound Profile: Crisp and noticeable over stock without excessive drone in the cabin.

Why We Like It

COBB has always done a great job of balancing performance and refinement, and this exhaust is a perfect example. It looks clean, fits right, and sounds better than stock without turning the car into a headache on long drives. If you want a premium OEM+ exhaust for a VA sedan, this is one of the safest bets out there.

Installed On Car

Construction Details

Mid-Pipe

At the front of the system, a high-quality cast flange is machined to accept the factory donut gasket for a leak-free connection. From there, 3" stainless steel tubing runs back to another 3" cast flange where it meets the y-pipe. A flex section is incorporated to add compliance and help reduce stress throughout the system.

Y-Pipe

The y-pipe begins as a 3" tube and transitions into twin 2.5" tubes using a cast split section. This improves durability and long-term reliability over traditional welded split designs. All three y-pipe connections use cast flanges to resist distortion and ensure a secure, leak-free fit.

Mufflers

The muffler sections attach to the y-pipe with the same high-quality cast flange design. Each bespoke COBB muffler features a single 2.5" inlet and dual 2.5" outlets that accept 3.5" dual-wall slash-cut tips with laser-etched COBB logos.

Gaskets

Multi-layer steel (MLS) gaskets are included for all connections to ensure a durable, leak-free install.

Confirmed Fitment

• 2015–2021 Subaru WRX Sedan
• 2015–2021 Subaru STI Sedan

Sedan only.

Specifications

• System Type: Cat-back exhaust
• Main Piping: 3" stainless steel
• Y-Pipe Outlets: Twin 2.5"
• Muffler Inlet: 2.5"
• Muffler Outlets: Dual 2.5"
• Tips: 3.5" dual-wall slash cut, laser-etched COBB logos
• Material: 304 stainless steel

Installation Notes

• Direct bolt-on cat-back for compatible WRX/STI sedan applications.
• Uses the factory donut gasket connection at the front flange.
• MLS gaskets are included for secure sealing at all remaining connections.
• Adjust slip-fit tips after installation for ideal bumper alignment.
• Re-check hardware after the first heat cycle.

What’s in the Box

• COBB stainless steel mid-pipe
• COBB cast y-pipe section
• COBB muffler sections
• Adjustable slip-fit tips
• MLS gaskets
• Required hardware (per COBB kit contents)

Compatibility & Disclaimers

Designed specifically for 2015–2021 Subaru WRX and STI sedan models only. Exhaust sound may vary depending on other modifications. Always verify fitment before installation and ensure all connections are properly torqued and aligned.