I have a 2.2l cobalt ls
I am wondering if it is a bad idea to put on a 2.5" header, downpipe + cat with a 2.25" cat-back
if you are gonna go to a 2.5 collector at the end of your header, than go 2.5 all the way. You prob could go with what you want, and not have a problem.
you might kill torque and throttle response with the 2.5. imo 2.25" is a much better choice. it'll be a little quieter too.
