When I was at the races this weekend my YZ was sound tested and it blew 101db with the stock exhaust. Not too bad, I thought it may have been a bit worse than that. I was hoping for 99db or less but I guess I won't get that unless I change to a quiet pipe. Just thought I would let you guys know, just in case you were wondering what they ran at. My pipe has about 15 hrs on the stock packing at the time of the test.