I was due for a change and put 9.5 qts. of GC in my 4.2L V8. The thing is, I had one 04 GC (green) and one or two gold (but without the caustic smell) and the rest were gold WITH the caustic smell (at least to me). Now, obviously I want to know if these are all compatible. Why the differences in the Gold's? The 04 didn't have MB 229.5, the gold did. Also, my oil that was drained was Motul E-tech 0W-40. So switching oils is no problem, right? Even though the 4.2 supposedly has like 2-3 qts. that don't drain and are always in the engine. Well, not the EXACT same 2-3 qts. but you know what I mean, haha. VW's new oil list doesn't have GC on it but the GC label carries the VW 502 (required) and the 503.1, for the high-output turbo B5 S4 and TT. So is everything A-OK?