Hey folks, that's a really useful topic! I've been reading it all due to the fact that I've been experiencing the same reduced power / limp mode at the track, most probably due to high coolant/oil temps.
Just to give some context, my car is bone stock except for the brakes (well, for now) and brake fluid. Stock coolant/water mix, without MoCool or other WW.
I've been experiencing "half engine" light after like 3 high speed laps, and it *always* kicked in at the end of the straight (braking from 125 to 40 mph) or in the subsequent slow turns after the straight. My car does have the stock OC, and oil temps exceeded 275 F every time reduced power occured.
I was thinking about joining the passenger side brake duct with the air duct to the OC for better flow (AFAIK they are useless anyway), I guess it would result in the approximately same amount of airflow as if I would fit the 335is or M3 air duct, but I would still retain the fog lights.
What do you guys think about that?
E92 335i M-Sport | Bilstein B14 | H&R ARB | Quaife LSD | AR Design oil cooler | Tarox Sport rotors | Carbotech XP8 | Toyo R888 | OZ Ultraleggera