My M2 V.A.L.E.'s out of the box are NOT road legal and they are LOUD!
TBR offers two inserts: The P1 Power Tip (minus 2-3 dB, while actually adding measurable HP gains from the middle to the top of the power band) and the Q1 Quiet Core Insert (96 dB). Both fit ONLY the M2 series.
I'm enjoying the "music" in New Jersey, USA, but will consider one of the inserts, once my neighbors or the local constabulary start complaining!
By the way, with a K&N air filter and a Power Commander, I picked up 5 bhp at the top end and about 6 bhp at 5,000 rpm, where I USE it. The throttle response has to be experienced to be believed.