I've got a single Flowmaster AT, and as far as single axle-backs go, there is simply no other muffler I would rather have. The Flowmaster has a nice, rough, rumbly sound to it, which I think fits a Mustang, and it sounds great both at idle and when walking on it. Drone is very minimal, the rolled chrome tip looks good, all around it's a good deal. I'm definitely happy with the Flowmaster as my muffler upgrade.