If your going to replace the muffler only, on the SE exhaust it is 2.5". Midpipes are 2.25 that Y into 2.5". On Cherry Bomb, I HAVE run the Extreem, baffled 2.5" single in to dual 2.25" out, loved the sound( Jerri still prefers it), but it a droner! So if u don't know much bout different muffler types, here's a quicky; baffled only mufflers , like Cherry bomb Extreem, Flowmasters, are loud cause the are baffled hollow chambers, think churchbells, that resonates-DRONE. Glasspacks are more like a tube, with small baffles on the inner surface, wrapped in fiberglass, then encased in a shell, as in Magnaflow, Corsa, and Cherry bombs other model than the one I had, so less drone. It all comes down to how loud u want it to sound inside the cabin.