I have just retro-fitted electric seats to my E46 320 Coupe (2003).
I wired a power and earth feed to pins 13 and 14 of the seat plug, (as suggested by some helpful person in this forum) which now means that the seat controls all work. The problem I have is getting the driver's side memory buttons to work. The manual says that the ignition must be on (pos 1 or 2), so I imagine more connections are required, perhaps an ignition live feed. I seem to remember that one more wire came to the seat socket, but this not connected in my plug. Does anybody out there know the answer???