Well 2 1/4" should be sufficient with having a few bolt ons (to maintain some backpressure-torque). Also removing the resonator will give you some rasp with an aftermarket muffler.
Hector
2003 Rally Red Mitsubishi Evolution VIII
257HP/259TQ
2005 Lapis Blue Mazda 6s
RET: 00 Cabernet Red Ford Contour Zetec ATX SUPERCHARGED
160HP/141TQ
