That's good information. I'm glad I read this. We are about to purchase a car to go N/E racing and I want to have it quiet enough to start it up with out disturbing the neighbors. We are wanting to make our car streetable as well so we can dirve to the Sonic for a burger on Saturday night, church on Sunday, and possibly to some of the local car shows that are close enough that I really wouldn't need to trailer it . I want to get the best of both worlds and like a lot of folks I'm looking for the quietest mufflers with the most power.
One other thing, what about mufflers with an X pipe set up? I heard that an X pipe can help with horse power and noise because of the scavenging and the design creates some noise cancelation. Is there any truth to that??