I don't know if it's any help, but what the hell...

My previous car 2002 530i was a great car with only one "breakdown". Stalled while leaving a green light, sputtered and stopped in the intersection, restarted and limped to BMW dealer. Turned out to be Crankshaft position sensor, replaced and no problems. Anyways, may not be related, but your post did bring back the memory.