Ok, I finally got the bmw running well and of course a new batch of problems popped up. I think my alternator might be going out, at idle it's putting out about 13.5 volts, but if i turn on the headlights or wipers it drops to 13 or lower and the engine starts to run rough. My other car(99 mustang) stays at 14 volts regardless of the load on it so I'm thinking maybe the alt is bad?

The other problem is with the starter: when I go to start the car(I put a push button for the starter) it takes several tries before the the starter will work. I can hear a click but it takes 4 or 5 tries before it actually turns over. I've found that if I turn the engine by hand a bit first it it starts every time. Will I be needing a new starter soon?

First off is to clean up the posts on your battery AND the negative and positive cable ends. Make sure they're brightened up too. Corrosion of any kind can produce the symptoms you're having with both your starter AND alternator. If you really want to do a thorough job, remove the alternator wires and starter wires and clean those too. Also remove the battery ground wire to where it is bolted to the battery tray and clean the connector and the mounting spot it bolts to...

Let us know if this works for you!