Originally Posted by Autobahn335i
as you have a 6MT you'll have far less heat induced problems. I've driven my car in summer heat on a tight course (= nightmare for 6AT coolant temps) where it would overheat within 2 or 3 laps, despite massive cooling upgrades. Same day I drove a friends 6MT for 25 minutes session without issues. He only had upgraded his stock OC with a Setrab core.
So in your place I would get the ER Sports upgrade, maybe even the dual competition package if you want to be safe in any condition.
Christian, at 102K miles I am just now replacing the radiator on my 6AT. I don't know if you've held our radiator, but it is probably the smallest one I have personally ever seen. Looks like it came out of a toy car. Despite this, your common speculation about the correlated heat issues with a 6AT is misguided. Yes the 6AT's radiator has the double duty of serving the transmission, BUT you forgot to mention that even the 1M, and 335IS, with their extra radiator, and manual transmissions, still over heat at the track. This is a twin turbo vehicle we are talking about here. Lap after lap, you will keep getting slower. I spend time hosing down my radiator between sessions, and make it through a full track day without issues. Arrogant 6mt owners, just start out among the leading cars, and end up at the bottom half, time after time.