Hey guys just purchase my 04 wrx and have a question on exhaust that i haven't been able to find on my search. Is it true that if you replace your up pipe that your check engine light will come on? Should or shouldn't you replace the dwn pipe, is this the same dwn pipe that is in the sti?

 

No, it's not true about the up-pipe. The PDE brand up-pipe does not throw a CEL. There are some that will. I've personally used the PDE and it's +. The downpipe should be replaced if you want more power there are 2 cats (catalytic converters) in the stock downpipe. This is not the same one as on an STi. Also, here the PDE brand will not throw a CEL. Here's the website www.pde-usa.com

 

most of the uppipe and downpipe's will trigger a CEL. There are some brands that design it so that it will not. However, both check engine lights can be easily fixed. The downpipe one costs ~15 bucks, and the uppipe fix is a dollar at a local radio shack.