Guys
We just checked Rich(Dukeboys) Which is 107db
My M3 is 99db on standard system.

Duncans classic uk with prodrive system was 103db

I still think everyone should not get to anal about it,So long as your car is within 3 to 5 db of the allowable limit you should be ok.

One more thing, the db meters from maplin,RS etc are all perfectly ok but only once calibrated, we use sound level meters for acoustic surveys at work and have had off the shelf meters read as much as 9db out compared to a calibrated meter.