I own a 2004 STI and im wanting to get an exhaust sorted for it. Im going for a cobra backbox to start with, and gradually get the whole system done (without the missus noticing ).
Question is, what size pipework do i want? the aim is to mod to 350bhp eventually and don't want to get the exhaust wrong!
any help is greatly appreciated!

 

2.5 will be fine at that power level

 

As above 2.5" will be enough,if you will going above 400bhp i would go with 3"


Jura

 

sorted, i thought the 3" would start to lose torque.

 

Just put the exact same question on!!!! Just helped me a treat as buying a cat bcak system of Ebay

 

Haha! i must have been writing at the same time as you!
Anyway, 2.5" box with 4" tip from cobra is ordered, hopefully unleash the burble!

 

Same here. But got a H&S one, pretty much spanking new off eBay for £120!!!!