Keep your stock cat-back and get an electric cut-out. My buddy Eric has a set of two on his 2002 SS and it's so fricken cool! The car cruises like stock b/c it is stock, then with the flip of a switch it goes from mild to wild! I don't know why he got two, but the advantage of an F-body is that you have a y-pipe and only need one cut-out. I'm seriously considering a set for my car b/c they're that much fun. If you have to get a cat-back the Flowmaster sounds killer and the SLP loudmouth is crazy loud!