my son has a 05 550 classic he wants a little more top end it does 85mph. i was wondering what gears it has stock and if i could change one to give a little more , or should i go a diff route clutch/spings ? i don't want his sled too loud , so i say no to pipe . i have never modfied any of my sleds always stock .ihave taken everything apart at one time or another.