I had my driver's side rear window shattered by a weed-eater thrown rock. I had the dealer perform the repair rather than a glass company. My main concern was with the regulator as well. If the regulator needed any programming, the dealer was only one capable of doing that.

I had my rear driver side broken not long ago. As others have stated, I'd definitely push for oem bmw glass.

I'd also be sure they do a good job on cleanup inside the door. Mine had a ton of small pieces of glass in the bottom of the door. Something that could drive you crazy with rattles later on if they don't get it all.