I didn't see anything in that link that supports having to change the oil more frequently than recommended. Just because the oil is clean on two engines (one at recommended intervals, and one at double the recommended frequency) doesn't mean that you need to do it twice as often as recommended.

On the other hand, here is a thread with pictures of an engine that followed the recommendations to 100,000 miles. And it isn't an M model running 10-60, so it is far more relevant.

http://www.xoutpost.com/other-bmws/4...intervals.html

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