In my Z4M I never had any issue regarding temps, not even on the hottest day. The new M3 you can punish like hell, no issue. 3.0 NA engine of BMW, no issue at all, E46M3, E36M3 3.0 also no issue. E36 328i no issue.
I have experience with all these cars on the Ring and the 335i is the only one having an issue, and it has it already in 2nd or third lap. So for sure the overheating issues are more pronounced then other BMW cars.
If you start tracking you will not have an issue, put when you really start pushing and become faster and faster you reach the cooling limits fast.
FYI, adding bigger ducts (the one of the 335is for example) really reduce the temps a lot. See my thread for more information.