I just put on a mustang tuning catted x with the one chambers i already had welded in the stock pipes,holy hell its loud. drone on the freeway is not much more than with the stock h and 1 chambers,but it is louder around town.above three grand it fricking screams, and up to about 2700 its got a good raspy tone,there is only a small rang 2700-3000 that it gets annoying. if anyone wants to hear it ill try to get a good startup rev clip if i can get access to a digital camcorder