i'm used to track my bike more than my car.
With a bike, you need to decrease the tyres pressure on track compared to road use. For example, with a ZX10R, you go from F 2.3 / R 2.5 to F 2.1 / R 1.9 !
I did not do that with the M3, i only checked that the tyres pressure were in line with BMW recommendation.
I'm surprised that you mention it could be too low for track, this is exactly the opposite that for a bike ? you need to increase pressure before track use ??
thanks in advance !