I guess it comes down to the definition of what a top shelf oil is.

I have never worried about the Castrol that I purchased being a Group III oil, as I believe that a Group III oil with good additives is better than a Group IV oil with average additives. The reason that Castrol does so well with that specific oil is that it performs, whether it is based on synthetic PAO base stocks, or a synthetic process to produce an oil with the same or very similar properties.

The lawsuit that Mobil 1 lost was in something like 1999. 12 years ago? I think motor oils have changed significantly since then, and I suspect that all oil manufacturers have reformulated their products.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue