I would suggest headers and then maybe do mufflers. Once you delete the cat, get different mufflers and run headers, you will only make yourself want to like the sound but after a while the highway drone gets old and in the end it sounds like crap WOT because its still a 3800. The only decent exhaust note from these cars is by keeping stock mufflers, going with headers and a nice big resonator. The borla xs do sound nice, but they don't make up for everything else.