Who has the best cat back system as far as performance gains go? I have stock headers and I just bought an SLP Y-pipe.

 

it doesnt matter...your running stock headers and a slp y pipe/there goes all your power anyway. most cat backs are with in a hp or 3 of eachother go to ls1sounds.com and pick out which one sounds the best to you. i will let you in on a secret flowmaster flows like ****

 

Yeah man, for this type of question you really need to use the search button. But its hard to tell you which is the best because you have stock manifolds and everything. IDK, GMMG or borla are my favorites.