Best Performance & Factory-Like Noise
 

I didn't even look to see if anyone else has posted this question because it is kind of backwards-thinking in the cycle community. One of our restrictions at competition is noise level. We have to be under 100db at .5 meters away and at a 45degree angle in respect to the orientation of the muffler. All that while reving at 10k rpm -I think its 10k rpm, or something close-. Does anyone have any suggestions for mufflers that are fairly quiet and still maintain low back pressure than stock? That would give me a starting point! Thanks in advance!