3" Downpipe Adapter - Aftermarket DP>OEM Subaru Catback

GrimmSpeed 3" DP>Catback Gasket
GrimmSpeed Subaru Donut Gasket

Current stock: 0

GrimmSpeed Subaru 3 in. Downpipe Adpater

  • Flared Adapter Transition!
    (Creates a smooth transition from your 3" downpipe to your OEM midpipe)

  • Flanged for OEM Donut Gasket

  • Indestructible Steel CNC Laser cut construction 

  • Simple bolt on installation.
    (With bolts included)

  • Will Not obstruct exhaust flow like other adapters.
    (Flared end guarantees smooth exhaust flow)


 Exhaust leaks seem to be an all-too-common issue with most modded Subarus. They tend to spring up out of nowhere and cause hours of troubleshooting headaches. The most guaranteed leak you will get though is if you run an aftermarket 3" downpipe to an OEM or OEM like 2.5" Exhaust. Compare our adapter to the competition and you will immediately see why we offer the best solution to finally end that pesky leak.

Cut from Steel and hand welded these pieces were born tough. With the ability to work with both flat style gaskets AND donut gaskets they cannot be matched. If that wasn't enough we flared out one end to just shy of 3" so that unlike the competitors, our adapter will not block flow! 

A Final solution to pesky problems, it's what you can expect from GrimmSpeed™


NOTE: GrimmSpeed 3in. Gasket and OEM Subaru Donut Gasket SOLD SEPARATELY

Fitment Note: Adapter is only intended to be used for connecting aftermarket 3in Downpipe to OEM style catback. It can not be done in reverse.


16 Reviews

Michal Niewodniczanski 19th Dec 2021


Great adapter of 3" down pipe to OEM catback. Fits perfectly

Rob 8th Mar 2021

3 to 2.5 exhaust adapter

Great product, used it on my g37s to mount a 3inch ISR y pipe to stock 2.5 inch mid pipe, just had to cut the 2.5 side that comes off the mounting flange!! Looked everywhere no one makes something like this for the Z or Gs very happy I found this in a fourm

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