so what's the actual issue here? Overheating is pretty general fairly common in turbo cars and there are many heat management/extraction methods. Is the turbo housing cracking? Is the coolant temperature above normal? Is the charged air way too hot?
I only ask b/c we assume the other manufacturers do turbo's better, but it's also likely those cars have lower tolerances. Examples would be Evos and STis...the engine management is nowhere close to the tolerance level in the BMW engine management software. There's a good chance that the BMW cars are just overly complex and have very restrictive tolerances for heat.
Just a thought, I wouldn't know any specifics, but does make sense to think about this aspect. In the Evo/STi world, owners would just work their cars hard on the track, then in between sessions, pop the hood and attempt to cool down the intercooler and intake piping and other cooling hardware. Additionally, stylistically, these manufacturers allow those cars to be designed with signficant vents to extract the heat. Something tells me BMW refuses to poke more vents in their beautiful F30's front fascia/hood or put a huge front mount intercooler or vents in the hood.
These are just the fronts, but the Evo and STis all have significant vents on the hood or behind the fender for cooling: