The Pypes M80 is a 2.5 or 3 inch in/out glasspack.

Alot of Mustang guys use these mufflers on their cars and as far as I've seen I'm the first F Body to run one.

I have mine installed with a 3 inch catback and the tone is mellow and strong, it's loud but not overpowering.

It's a straight through design. If anyone is considering an exhaust upgrade then I highly recommend this muffler. It can be had for about 60 dollars shipped from Summit Racing.