Originally Posted by Blueboost
Is there any difference between an 04-05 sti oem downpipe and a 04-05 wrx oem downpipe. Does the sti breath better or is it the same setup?
I don't think you are going to gain much of anything going from the stock WRX DP to the stock STi DP with all things being the same. Both have a big cat that is the biggest restriction. For power increase I would go with a aftermarket DP without a cat or if must have a cat then get one with a high-flow cat.