I run the MIP tranny on a couple of my B5Ms and they are good for 20-30 degrees. I cannot believe how much heat they soak up. Its not as hot as Vegas here but a few race days have been 100+ and the track has been over 125. I'm pretty much the only one who can run a 7 minute main and not come off at 185 or more. I have the timing on one of the cars maxed out and have not had to gear either car down. If heat is an issue they are the hot ticket.