GrimmSpeed Stock Downpipe to 3inch Exhaust Adapter

2004-2021 Subaru STI / 2002-2014 WRX


SKU: 077046We price match!

In Stock

Make sure you install your aftermarket cat back exhaust correctly without any leaks with the GrimmSpeed Stock Downpipe to 3inch Exhaust Adapter from Subispeed!
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  • Flanged for OEM Donut Gasket
  • Machined lip centers 2-Bolt Gasket
  • CNC Machined Steel Construction (Zinc coated for durability)
  • Simple bolt on installation (Supplied with quality hardware)
  • Includes GrimmSpeed 3" 2x Thick Gasket (For a PERFECT seal!)

Install Your WRX or STI Cat Back Exhaust the Right Way

Exhaust Leaks are a Thing of The Past, especially with the GrimmSpeed Stock Downpipe to 3inch Exhaust Adapter. When installing a new cat back exhaust, exhaust leaks are a super common problem especially on the 2015-2020 Subaru WRX and STI’s. The most common issue we hear about is from running an OEM downpipe with an aftermarket 3” cat back exhaust without a proper adapter. Use this adapter to allow you to keep your stock donut gasket for the best solution to finally put an end to that pesky leak.

Quality Made for Peace of Mind

CNC machined from mild steel and zinc coated for durability and longevity, this thing will outlast your car. Don't waste your time trying to get your OEM downpipe to seal without a donut gasket. In a short amount of time, they rust and corrode and will prevent you from ever getting a good seal with a typical flat gasket. Re-use your stock donut gasket along with a GrimmSpeed 2x Thick 3" Gasket (included) for a perfect seal on the first try! A final solution to pesky problems, it's what you can expect from GrimmSpeed.


  • 2015-2020 Subaru WRX
  • 2015-2020 Subaru STI

8 customer reviews

Average rating
(based on 8 reviews)
Ease of Installation
Fit / Quality
Overall Satisfaction
  1. u need thid

    By Jer November 20, 2022

    Subispeed sent this out in 2 days . pick this up with your 3in exhaust and a new donut gasket and you will have no leaks

  2. Perfect

    By Nest October 30, 2020

    Perfect Fit and delivery was quick. They came through with next day delivery. usually when I order things, next business day usually means 2 business days when living in hawaii. Ordered it on Wednesday night. Shipped out the next day and got it in this Friday morning 👍🏼

  3. Mandatory!!!

    By Kyle October 11, 2018

    If you are installing a new cat-back exhaust system, then you NEED this! Pretty straight forward and does as intended.

  4. Perfect

    By Ryan February 24, 2018

    Excellent customer service! Ordered and delivered within the same week.

  5. Sure glad I had it

    By Paul August 23, 2017

    Purchased this kit to install a Q300 on my 2017 WRX. The additional $39 was money well spent, if you are installing a cutback to your stock down pipe do yourself a favor and purchase this.

  6. Great part

    By Mike August 6, 2017

    Got this to pair my new invidia r400 to my stock down pipe. Great part and coupled with a exhaust gasket that came with the cat back there is no way it will ever leak. The only bad part was the nuts and bolts where a little to small for the holes that where in the invidia exhaust flange, so I opted to use the invidia hardware. As always great quality from grimmspeed and still love the laffy taffy from the subispeed guys.

  7. Great Fitment

    By Frank Stark October 4, 2016

    Fits great and eliminates any potential exhaust leak, I used this for my Invidia N1 Catback on my 2016 WRX Base and it fit great.

  8. Fits And Works Perfect

    By Daniel July 27, 2016

    If you're going to a cat back system definitely spend the extra money and get this adapter. Really easy to add on and gives great defense against exhaust leaks when tying to a stock downpipe.

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