what are you looking for? Do you want a slip on or full exhaust? Do you want the noise factor or do you lean more towards performance gains? What type of sound do you want from your bike? There are sound clips on the internet for most of the popular pipes and a few on here if you use the search function. Personnally if you were going for sound and slip on D&D are some of the loudest and personally i think two brothers and micron have the best tone without being to annoyingly loud.