I ran my 328xi at the Summit Point this weekend. Like rheemix I don't have any added cooling mods. I noticed on day 1 of the weekend, on the third set of runs I had some power loss I assume from the oil temps getting high. No other problems during the 7 set of runs I had throughout the weekend.
Tires will help alot. Do you have sport suspension?
daily: E90 LCI 328i #AWE90
track toy: E36 M3 #bcRCR