[bm49]

Thanks for the tyre pressure advice ayao. By the look at the wear patterns, 32 psi hot was too low and next outing I will try your higher pressures and try to remember to take my laser pyrometer to check temperature distribution across the tread.
You are right about the conflict with the LH side radiator. The 1M setup seems to incorporate the optional BMW Performance kit(can't remember the correct package name) that is available for all non-M models. To cope with the small power increase that came from the Tune component of the package it included a bigger cooling fan and the supplementary radiator that slots in on the usually empty LHS front.
If doing regular or serious track work you would need to get the ER dual oil cooler kit and fit a larger main radiator. I dare say ER have probably done some conversions on 1M's already. Replacement of the hose setup that diverts coolant to the supplementary radiator on the 1M should be pretty easy by using standard 135i parts. Since fitting the larger radiator my regular oil temperature for road use has dropped from 110C to just over 100C.