Yes the BMW metallic paint is rock hard. I had some minor surface marring and used a 7424XP, orange pad and M105. Didn't do as good of a job as I wanted. I needed a stronger and smaller pad; for next time I bought a 4" backing plate and some yellow pads.
And lighting is absolutely critical ... I used sunlight but resorted to a flashlight for the sides of the car. PITA. Next time I will buy a 3M sun gun.
2011 BMW E92 335i - Le Mans Blue/Black, 6MT, M Sport package