I recently added flowmaster super 40's o/o 2.25" and I know it will take a little time to get louder but, I keep seeing setups with pro-chambers and SLP loudmouths? What are these items? What do they do? What else can I do to get my mustang gt louder? Should i take the catalytic converters off? should I put on X pipe? I really need help!!!!! PLEASE SOME ONE!!!!!!! I am upset that I didn't get the sound I want!!