whats the diff...

between a cat system and a make your own? what is the best set up for gp??

what are you talking about

sorry i was refering to like the borla and corsa cat back exhaust compared to like the flowmasters and what nots is there any difference besides price?

Stick with stock. I'm finding out the hard way recently there is no such thing as a nice sounding Grand Prix exhaust. I'm on my 4th setup right now and I'm still not happy.

Eh your too picky. I am very pleased with my D/Ped, res. deleted, F/M 40ed exhaust. I think it sounds great.

I love how my exhaust sounds. FM 40's (not super) with a set of resonated tips to quite down the drone.

i dont like GP exhausts too much. I kinda like mine, but the headers just destroyed what the sound was before.

Borla and Corsa are expensive