For those of you with the 3.0SI engine, this may be of help. Mine has always had an idle that hunts after starting until hot. Recently, as this has always been main dealer serviced to their (IMHO) ridiculous oil change schedule, I decided to do it myself. I decided to do away with the BMW 0W-30 water that purported to be oil and used Millers nanodrive 5W-40 NT+ as to me at 88,000 miles the engine is bound to be a bit worn and clearances will be bigger than when new. Guess what? After three days, idle is rock solid! Result! No, technically the Millers is not LL04 (though I think it is actually far higher spec than the original oil) but then I do not believe any oil, even snake oil should be in an engine longer than twelve months or 6,000 to 10,000 miles. If you do some reading you will find that combustion products will break oil down eventually just sitting there so it makes sense to me to change it. It is cheaper than an engine! Just my experience and I hope it helps someone who is tearing their hair out chasing after the uneven idle. 
