I don't know anything about the "older bmw bosch fog light system" but if you don't want to do too much work I'd look around in a junk yard to find all the brackets for the fog lights from a similar model and make sure your car has the connections for it (probably does). Then just transfer the hardware and wire it. If you go this route, u might ask for a wiring harness and a switch for the area near the steering wheel.

This reminds me of the project I did with converting my crank sunroof to a motor. Wasn't really hard. The hardest part was finding all the stuff I needed-but the guy at the junk yard knew his stuff and was really helpful. Bolting it all in was the easy part (except getting a connection in the fuse box- needed small hands.)

Good luck whatever u choose to do,
Nathan