I had to redo my whole exhaust (Cracked manifold). I bought a Drake Header, installed that, then took it to an exhaust shop to get a new system in.
I got the flowmaster 40 series, single in dual out. It sounds awesome! I also took out my CAT (No emissions testing in Florida) so I don't have to worry about that. I noticed a power increase when I went from stock to what I have now, and I love it.
I WAS going to get the Banks Monster exhaust ($$$) but that never happened. I'm happy with what I have now, and I saved money on it as well.