PBMS GRB/GVB Downpipe – 2.0L Twin Sroll JDM



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Brand new PBMS 3 inch Downpipe to suit 2.oL GRB and GVB models.

Suits factory cat-back exhaust and performance exhausts that are designed to bolt onto factory downpipe.

Upgraded replacement for factory downpipe.

Note: May cause the engine check light to come on if vehicle not tuned or ECU not adjusted to suit.

Discuss the suitability of this downpipe for your vehicle, please contact us.

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Want to push more power from your standard Subaru WRX STI GRB/GVB?

The best place to start is with a high-flowing downpipe!

The factory Subaru downpipe is restrictive with small piping and a catalytic converter. This makes a downpipe the most restrictive part of the exhaust system, and the first place to start to improve performance.

The solution is a PBMS high flow downpipe, made with 3 inch mild-steel piping and a catalytic converter delete. Possum Bourne Motorsport have designed and developed this to be a multi-purpose system to suit mild and wild power goals. It is a direct replacement for the factory downpipe and can be fitted to a factory 2.5 inch cat-back exhaust system (to keep the car quiet and stealth) with the use of the 2.5 step down adapter. It can also be used to bolt up to a full 3-inch cat-back exhaust system for those looking for more power.

PBMS recommend using a high-flow downpipe on all vehicles looking for more power.


  • Higher exhaust flow — resulting in more potential power
  • Less turbo back-pressure — improving turbo spool
  • Engine sound — the higher flow will give the engine an angrier sound


This is compatible with Subaru WRX STI Japanese Import GRB and GVB models only. These are EJ207 (2.0L) powered vehicles equiped with a twin-scroll turbocharger.

Please contact us if you are unsure. Please have your vehicle registration handy.

Recommendations (Not included in price)

  1. We recommend new gaskets are used when installing
  2. The turbo heat shield should be retained however may require minor modification to fit
  3. We recommend having the vehicle ECU reflash tuned to ensure engine safety, make the most of this upgrade and remove any check engine light that may be associated with the catalytic convertor delete.

Recommendations and next steps (Not included in price)

Once you get a taste for power, you may find yourself wanting even more! The exact requirements to make more power do vary between models, but Subaru engines respond well to further intake and exhaust modifications. The PBMS Stages of modification are listed bellow:

Stage 1: High flow downpipe

Stage 2: High flow downpipe and PBMS Reflash tune package

Stage 3: All the above, plus a cat-back exhaust system

Stage 4: All the above, plus a cold air intake system

Stage 5: All the above, plus a front mounted intercooler system

Stage 6: All the above, plus an upgraded turbocharger, injectors and fuel pump

Stage7: All the above, plus a purpose built performance engine

Stage 8+: Custom upgrade kit and engine to suit customer requirements – contact us for more information

Please note: This downpipe does remove the catalytic converter from your exhaust system. This may not be legal depending on when your vehicle was registered. The check engine light will typically come on one this has been removed. PBMS can programme this out when tuning the vehicle ECU.