I had my ceramic tint on my e92 for over a year now. No scratching at all. Make sure you take your car to a reputable shop. The e92 has a lot of dot matrix area on the windows.
2011 E92, mineral white/red interior, sport, navi, premium, CA. Current mods: 15% ceramic tint, black grills, painted reflectors, wrapped side mirrors and front blades, HID fogs, Forestar F14, KW Street Comfort