Just right, that's the stock 1999-2004 V6, GT, and Mach 1 exhaust diameter. Keeping it 2 1/4" (such as with a GT takeoff catback for instance) maintains your low end torque. I am sure others will post recommendations for various 2 1/2" diameter aftermarket catbacks, but I would use a GT takeoff if it were me converting to duals on a V6.