I think its 99dB at 1 metre from the tailpipe running at two thirds of the engines maximum revs and must have at least the same amount of silences as manufactured, mine 4.6 V8 was 109dB at tickover, end of event, earbleeder but nice.
Add jubilee clips to stop suspension springs detaching for the day and you will pass scrutineering if dislocators are fitted.
Make sure bumpers don't offer any advantage over standard, length and height and width etc, and I think if they're on a 90 etc they have got to be 3" deep and parallel to the body, check regs, i've been measured a few times with alternative bumpers.
Total offset of wheel must not exceed 4" or 100mm from outer edge of hub, most do, but some Mach 5's don't, they had a considerable debate on mine last year and told me they were only just 4 inches I was lucky, its funny i had them made at four inches wasn't that lucky, but only just 4 inches.
But don't forget to smile, you're there to have fun.
Good luck