Just went thru the same process over the weekend. Ice off an 18 wheeler shatter the whole windshield. Went thru statefarm, which reffered me to glass max. I talked to them and without running my vin., says there are a bunch of aftermarket windshields for the x5. So I do my research and decide I want to go with BMW oe glass.
Insurance only wanted to pay for aftermarket glass ($450 installed @ glass max). After a day of phones calls going back and forth with the claims dept. I get lucky and speak to a claims rep that looks up and vin. and approves OE glass for my truck, I ask her to write it in the notes that it has been approved for OE glass replacement. I could have just went with OE glass and install at a glass place but wanted to get everything at the dealer. At the end of day, went with the dealer and paid $200 out of pocket for the peace of mind of getting it done the right way. If u search the foru
there are a few posts about aftermarket glass and the fitment issues and wavy glass. Ar can probably chime in on this, but I remember reading that BMW uses a different install process (assuming they don't use 3rd party). I just feel more confident with the factory install tolerances compared to a mobile service that rips out the old glass and just slaps adhesive and wait an hour and it's done.