OK, the 325.....does it not have a VDO already in it? Ok anyway if not,........still thinking..........OK. The distributor for your car is on the front passenger side, right? If so, I think the BMW 6 cylinders run off a crank trigger. Tell ya what country kid, instead of babbling here, let me go look at my cars and see what I can find out. Ive never put a aftermarket in a BMW 6 cylinder, just the 4 cylinder. Ill get back to ya on it.
as far as what wires go where, i believe green is ignition coil, red is +, black -, white goes into the headlight dimmer. I believe that is how mine was, your smay be different, they have the manulas in *.pdf on their website (sunpro.com maybe?)