What thoughts have you got for getting the noise levels lower Adam? Two mufflers?
The noise level on the outside isn't all that bad. I passed at around 94-98db last year depending on how it was measured. The problem is in the cab. At full throttle my db meter recorded 122db with the firewall installed and windows closed. With the windows open it was around 114db. This year I mounted the motor back on rubber mounts and it is notably (I wont say quieter) less loud in the car.