I was wondering, by adding a high-flow cat and a downpipe to my exhaust will it void my gm warranty? Thanks

 

ummm... I doubt it.. but keep your stocker just in case they say something about it.
and since the stock cats suck... I don't think they'd mind

 

according to my dealer, it will only void the part of the warranty that will cover problems with your exhaust. but, if you later have a problem with something else that has nothing to do with your exhaust, you will still have your warranty to cover that problem.

 

Exactly plus even if something did go wrong with the exhaust or something, they have to prove it was the downpipe that caused it. Just get the 2.5" w/cat from cobalt-addiction and you will be good to go my friend.