I have recently found and installed a new set (4) of guide brackets on my sunroof. Here is the information on where I found them.
A search of the BMW parts sites online provided a part number (54-12-1-815-185) and I ordered them from “bmwpartscenter.net”. http://www.bmwpartscenter.net/partlo...?siteid=215996
The part number shown on the part is “100 556 612”.
The parts were $7.48 each. There was $4.00 extra shipping since these parts had to come from Germany. The standard shipping and handling was $11.95. The total for all four parts was $45.87. Not too bad for having a sliding sunroof again.
The parts ordered are a little smaller than the original but they did the job. I extended the slot on the back end of the parts to get a little more adjustment. This was the only adjustment I made and it may not have been required since the gaskets keep the panel centered.
I hope this helps other sunroof owners.