From the MLR website:
107db limit.
Spa generally has higer noise limits than most UK tracks due to the fact it is in a rural location, also MLR organised TDs tend to be higher too due to most tuned Evos being noisy!
Suspension wise, you might want to lower it a tad and certainly run stiffer than equivalent OEM. Regarding camber, i run more -2.5deg as standard but don't drive my car so much on road these days. I did Spa last year on OEM suspension and the car was rolling quite badly in the slower corners like 'La Source' hairpin and 'Rivage'.