The Comp axleback sounds tuff, but the AFM is annoying even with the stock cats and manifolds in place...Add headers and it will get even worse, IMO u need to turn of the AFM and thats what I did.
I also added a Magna X-PIPE MUFFLER 14386 to my car, I love the sound..
I will be adding HI-FLOW CAT PIPES next, I am not going with headers on this car.
JMHO