Generaly 2.25" exhaust is the optimum for the 22r ,motor.

I have a 22-re and run a standard glass pack. ITs not too loud when its new, but after a year or so it gets a little annoying. <img src="/forums/images/graemlins/smile.gif" alt="" />

Try the Dynomax turbo muffler. They put out some great sound and are not too noisy.