Try
http://www.thunderhill.com/html/driving_school.html
They run in 3 different groups, have instructions around to guide you. I'm not sure what the db limit is on the track, but I haven't heard of anyone having problems - it is out in the middle of no-where. it is not a pace-car parade lap, its open lapping, with strict passing rules (only on certain straights with a wave-by).
-nathan