The stocker is around 98db. To me it feels corked up over 6k rpm but it could be that the engine is still a little tight after 500 miles on the bike. Probably going to have to play around with the jetting with the full system. I've got a JD kit for the 450/510 around here somewhere so I'll have some needles/jets to play with too. I'll post updates here as I get to it.