I once got a warning for the flowmaster muffler on my CRX Si. When I asked another cop about it, he said the first one gave me a warning because he did not have a decibel meter on him, and they always get thrown out of court because some riceboy shows up with a lawyer who asks the cop to provide proof that the bike is too loud. If he did not have a decibel meter in hand and walked around your bike while you were revving it, how can he say it was too loud? Are his ears calibrated and certified?
There is your argument for dismissal. Whether you need a lawyer or not, I don't know, but I thought I would relate my experience so you can beat the chicken#$%* charge.