I remember reading somewhere that SLX Professional was basically the Castrol Syntec 0w30 sold in the States, which is sourced from Germany. Came across the stuff for the first time today, at a German parts specialist, and on the front of the label it had BMW LL-01. It was sourced from Germany, and met SL/CF and ACEA A3/B3/B4. Here is the spec sheet. Is this the same stuff as GC?