After thinking about it, I can confirm that there is no low light indicator. Here is my DIY, http://www.e90post.com/forums/showthread.php?t=367729
the oil was low at one point during the oil change process (while I was sitting in the car and shifting through the gears) and no oil light came on. See Steps 9-11.
If no codes are being thrown use Chevron Techron fuel injector cleaner (concentrate). It solves rpm fluctuating upon cold start-up. Also, for most BMW problems start off by scanning your car with the Peake Research Tool. It contains the actual BMW codes. If you want to register a newly installed battery for free (just buy a $10 cable) and google/download BMWLogger