Well without going into a long discussion of comparisons I can say I've tried all of the above mentioned mufflers and can say that I believe my Borla Pro XS is the quietest I've heard. I bought them and installed them tti headers,3" x pipe to the mufflers and 2.5" tailpipe and the result was unintentionally dissapointing it was so quiet. It was quiet enough to make me think about a trip back to the muffler shop to change them out but I've grown to love em since. They could pass for a stocker any day- only the cam lope gives it away as being something else.