No thread sorry, just experience with my E39 540. Some of the clips on the sill plates cracked on them, but with the X3 I guess they're a bit younger and less brittle and didn't break. I don't tend to use a tool, just my fingers that way you can feel where the clips are. My technique, go underneath the plate on the carpet side, locate the first clip and carefully pull up, move to the next clip.
The Camera was a no brand name device from mainland China, supplied via the Dynavin agent in NZ. It was releatively cheap but it does have a Sony sensor in it and not a CMOS, so the image quality is good, even at night.