I got this info from Mr. Hand's "Silent Power" CD that I purchased awhile back. I do not have a web address to help you. I can direct you as to where to purchase it though. ($10) It has a good selection of exhaust sounds , both 2.5" and 3", with and without an "X" pipe. The mufflers were tested for flow rates, measured (case size), and give MSRP and actual cost. They also give the decibel levels for 750, 2200, and 3500 rpm. Well worth the money IMO.
Rob
