SuperTrapp muffler discs
I have used Supertrapps on several BMWs, Mazdas and motorbikes. Needless to say I think their great.
They do have some drawbacks.
The bolts holding the disks can sease. (not good)
The sound they make is the you love it or hate it sound. ( Bad to hate after you spent your money)
They cost $$$$
The good is
Sound can be changed.(The disks and the packing is adjustable)
The mufflers can be moved from car to car.
People will ask you a lot of questions and hang around your car( this could be in the bad section)
Whip