Spiky, do you think you can loose 8 decibles in a distance of 5m ?
Donington is 98db so 87db is less than half the noise level they allow, i personally don't think its possible, most cosworths at donington are about 97db also.
Not trying to put people off though, but £140 is a lot to waste, i think Donington to flyby laps for a noise test to be honest.