Re: Question about idling rpm.
What is the RPM you have on oyur car? 320i E46 has a drive by wire throttle control i.e it is not connect mechanically to your throttle body intake. normal RPM is 600, a variation, if not at cold start, could mean too many things including the MAF, position sensor or even a dirty fuel line! a simple diagnostic should highlight a major problem if any.
-rohit