Aongus

I can't speak for anyhting but he Loudmouth II's. Mine are on an 02 GT. I still have the factory cats & header. The Loudmouth's have GREAT quality. They were super easy to install & like stated earlier, they have a great "race car" type sound when you get on it. At idle, they sound about stock. Minimal drone at speed too so that is a plus (in my book anyway). Hope this helps.