M4 M Performance Exhaust - noise level?

[UmpaLoompa]

Hi all, hoping for some assistance from the masses of PH!

I've booked on to a track day at Brands Hatch in December alongside a mate who is currently driving an M4 with factory fitted M Performance Exhaust, and we're a little concerned about the noise limits (Static 105cB and drive by 92dB).

My question is whether anyone has tracked such a set up and what noise levels they were putting out? Clearly atmospheric condition son the day will vary but any indicative guidance would be greatly appreciated!

Thanks in anticipation