I know additives to reduce friction were not part of the excellent article, but I just got to thinking. Since most of our BMW's are dry clutch, would there be a benefit to an oil that isn't blended to prevent wet clutches from slipping? I just wonder if Spectro blends oil for BMW with that in mind?
Mobil1 (car oil) is designed for high performance engines and flat tappet engines. The 15-50 contains nominal 1200 and 1300 ppm phosphorus and zinc. The Mobil1 V Twin 20w50 oil according to them is blended to be used in wet clutch applications also used as transmission oil.
I used Mobil1 15w50 for years in my Harley Davidsons, and they never did over rev and blow up because the oil was too slick causing a runaway engine effect.
I also used Mobil1 15w50 in two different oilheads with no problems.