all are good. its just a matter of how you want yours to sound. ie american musle get flows or magnaflow. send some one to the doctor with bleeding ears, get Lound mouth I or LM II. i have the magnaflow catback and at first it sounded less then stock. but put a few miles on it and it got a little lounder. it still was not lound enough for me so instead of getting rid of it and lose$$, i got cut-outs that i can controll
