I raced my FZR400 for 5 years on a can that was too loud for the racing regs
It had a Vance and Hines race system putting out a measured 109dB!
Funny thing was that whenever I came back off the track to the pits and caught site of the sound tester man I always killed the engine and coasted as if out of fuel. Ah those were the days.
It did sound awesome though.