2 1/2" Mandrel bent pipe with a Bullet muffler I think. If you are going to crush bent it you would probably go with 2 1/2. I've had three or four mufflers under there but I'm pretty sure that this one is a Bullet.

I think it sounds better than the Dynomax and the Magnaflow that I've had in the past.

Keep in mind that you are also hearing the K&N also.