Here's a thought, not stirring the pot on this issue just throwing something out there. BMW engineers recommended interval is 15K miles for oil change/service. Given that they deal with this every day, day in and day out, why would you think that is not acceptable. I've seen the oil come out of my e46 325 at 15K and it's much cleaner than any other vehicle I've ever owned that went on a 3K schedule. BMW pays for the maintenance, they also provide a very nice warranty on the vehicle, do you think they would provide either if their research did not substantiate the inspection and maintenance intervals they recommend? On turbine engines (Rolls-Royce BR700 series) we don't change oil, only add
using a synthetic oil. Again it's something to think about for all you naysayers that say no to 15K changes.