I'm looking at maybe purchasing a new exhaust system for my 99 gtp supercharged but not sure what to look into. i would like something that is fairly loud when you step on it but not always obnoxiously loud. also i am not sure if its worth it to get an entire cat-back or just a muffler(s)? would i see worthwhile power increases with a cat-back? i dont want to spend too much money either. Thanks!