I think the limit is 106db at about 3/4 revs. But when I was there last they were only checking the cars doing track day. None of the drift cars were tested. I thought I was going to have trouble as my car is quite loud, never had a proper sound test but on some shit phone apps it ranges between 100-105 on idle. Thats with sr20 and nur spec exhaust with no silencers.
I'm still really tempted to book on this. I need to save for holiday but drift day is so tempting.