Mobil 1 0W-40 is perfectly adequate for these engines as long as you maintain a *sane* oil change interval. The ONLY reason BMW went with the LL-01-spec is because with the introduction of the "All Maintainance Paid For 4 Years" scheme (and it`s attendant long-interval oil changes), they needed an oil that could be pushed beyond 20,000 miles without inducing catastrophic engine failure. Hence, LL-01.
The road goes ever onward....
*Please support the Disabled American Veterans*
When faced with choosing between two evils, always go with the one you`ve never tried before....