Mishimoto - Cat-Back Exhaust - 15-19 Subaru WRX/STI

MishimotoSKU: MMEXH-WRX-15

Sale price$1,159.95

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Mishimoto - Cat-Back Exhaust - 15-19 Subaru WRX/STI

Here at Mishimoto we've decided to expand our line of 2015 WRX parts. Mishimoto is proud to release the 2015+ Subaru WRX/STI Cat-Back Exhaust. One of the biggest complaints 2015 WRX owners have is that the stock 2015 WRX exhaust systems lack an aggressive tone. The Mishimoto 2015 WRX Cat-Back Exhaust allows the entire system to breathe easier, providing horsepower, torque, and a rich exhaust tone. 

After comparing many different muffler sizes and designs, Mishimoto engineers chose oval mufflers to help prevent highway drone but still provide an aggressive exhaust tone for your 2015 WRX. During dyno pulls with the 2015 CVT WRX, Mishimoto saw gains of up to 9 whp and 8 wtq using 93 octane fuel while maintaining safe AFRs on a stock tune (see additional images for dyno chart). This 2015 WRX exhaust installs in under one hour and features quad 3.5" staggered double wall polished tips. The Mishimoto 2015 WRX Cat-Back Exhaust provides an extremely aggressive turbo and exhaust tone under acceleration and boost, giving you that sweet sound you've been looking for!

The Mishimoto engineers designed this WRX and STI cat-back exhaust as a four-piece design, comprised of precision TIG-welded 304 stainless steel. This allows a smooth exhaust flow from the 3.0" 2-bolt exhaust flange all the way through the 2.25" Y-section. To top it off, this 2015 WRX exhaust includes two 2.25" V-band clamps, a 3" exhaust-band clamp, a new 3" 2-bolt flange gasket, and all stainless steel hardware, so you don’t have to worry about rusty hardware!

For 2015 WRX or STI owners looking to get the most out of their WRX, this 2015 WRX cat-back exhaust mates perfectly with the Mishimoto Subaru WRX Performance Downpipe. The Mishimoto Subaru WRX Cat-Back Exhaust, like all of our parts, comes with the Mishimoto Lifetime Warranty.

  • Direct fit for the 2015-2019 Subaru WRX/STI
  • Dyno-proven maximum gains of up to 9 whp and 8 wtq and peak gains of up to 4 whp and 3 wtq using 93 octane fuel while maintaining safe AFRs on the stock tune (2015 WRX w/ CVT)
  • Extremely aggressive turbo and exhaust tone under acceleration and boost
  • Mates with the Mishimoto, stock, or most aftermarket downpipes
  • Installs in under an hour
  • Designed with oval mufflers to prevent highway drone
  • Quad 3.5" staggered double wall, polished tips
  • Full 304 stainless steel, mandrel-bent construction
  • 3" to 2.25" exhaust split helps maintain proper exhaust velocity
  • TIG-welded to perfection
  • Mishimoto Lifetime Warranty

Purchase Includes

(1) Stainless Steel Mid-Pipe w/ 2-Bolt Flange
(1) Stainless Steel Mid-Pipe to Y-Section
(2) Stainless Steel Mufflers w/ Quad 3.5" Staggered Double Wall Tips, Polished
(2) 2.25" V-Band Clamps
(1) 3" Exhaust-Band Clamp
(1) 2-Bolt Flange Gasket
(2) 3/8"-16, 1-1/2" Hex Bolts, Stainless Steel
(2) 3/8"-16 Serrated Flange Hex Nuts, Stainless Steel
(2) M10 Washers, Stainless Steel
Mishimoto Lifetime Warranty


This product has been designed to fit both manual and CVT transmission vehicles.

Mishimoto does not recommend installing this cat-back exhaust and the Mishimoto Performance Air Intake with the stock ECU programming. It is recommended that the customer is able to retune the vehicle’s ECU after installing the cat-back exhaust and the intake. Power gains will vary depending on the type of ECU tune that is applied to the vehicle.


2015-2019 Subaru WRX
2015-2019 Subaru STI

Engine Codes

FA20DIT, EJ257

Chassis Codes


Weight 42 lbs


3.0" from 2.bolt flange to Y-section
2.25" Y-section to mufflers

Flange Material 304 Stainless Steel

Pipe Material 304 Stainless Steel

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