I also did a similar type setup straight through tenzo r muffler. It has a deep tone after driving the car about 30 mins or so but before that nothing much the sound the exhaust makes is less than a greddy evolution. So im figuring like 3 or 4 more decibals then stock. To make it louder have custom piping made and a highflow cat. I didnt buy a brand name exhaust for 3 reasons. 1: they cost 400-600 2: They only give like 3 hp which isnt worth it for me and 3: when i go turbo im gonna have to do a custom exhaust around 3" or so for the least backpressure and not many companys make them.. sorry for rambling on but ya get the idea