I hate the slp exhaust. To me, they sound like ****ty glass packs. You could do one of three things. Get a catted h-pipe, get a different cat back, or do both. If it were me, I'd do both. My cobra has a bassani catted h-pipe, and a set of flowmaster 3 chambers, and its plenty loud, and it sounds great too. Everyone has their own taste in exhaust sound, but I think for you, you're gonna have to change the whole set-up.