Just reading through and had a thought, may be wrong, but surely all the turbo'd cars run air-air intercoolers to reduce the temperature of the inlet charge to an acceptable level?
Admittedly if you're starting with a higher temp then it might not get to down to the right level, but it's certainly not going to be as high as an open normally aspirated engine that the DaveF/CAI kits were designed for.
On the dirty filter front, my old e36 318iS always benefitted from having the battery disconnected when the air filter changed. The car had the ability to learn and adjust to the airflow available. Resetting the ECU remove the custom part and improved the drive no end...
Maybe the newer tech doesn't do this but I'm look at 40k out of an original filter if I go by BMW service intervals. Can the car go that length without adjusting to the decreased airflow from the dirty filter?