Well that was a fun day - beemer was handling great, and was fast... most satisfying moment for me was closing a gap on a lotus elise so he had to move over - I always through that lotus elises were sposed to be the bastion of sportscar motoring, but we're faster in our £800 bmw saloon (albeit with a few highly effective mods!)
unfortunately day was cut short around midday, diff started making an alarming whining noise and on inspection appeared to have a drip of differential oil - suspect it was running a bit dry. Still, might use this as an opportunity to change our diff from a 2.93 to a 3.44, which would really help how it feels to drive on track!