Just recently did a valve cover gasket replacement on my 01 330i @67K. Slight leak from some of the rubber hold-down bushings, but the gasket itself was ok abeit a bit stiff. History-Previous owner had done ~15K oil services at the dealer and they used the BMW High Performance Synthetic 5W-30 (verified through dealer service records). It had about 13K on the current fill of "dealer oil" when I bought it. UOA right away showed pretty decent results despite the higher mileage OCIs. Regardless, I did an ARX treatment and then went onto GC with 7500 mile OCIs. Now before I get the "this thread is worthless without pics" banner, I did not take any. You'll just have to trust me . I pulled off the cover with a bit of trepidation, expecting to see at least some evidence of deposits. Especially with all the controversy about the BMW oil and all the horror stories. Well......it was absolutely spotless. Only area that had any of the typical reddish deposits was the filler area of the valve cover. Even that was minimal and wiped right off. This area gets the deposits from moisture and lack of air flow (highest point in valve cover area). There was a slight gold "patina" on all of the parts, but this is probably from some additive in the BMW/Castrol oil that stains the metal. It is purely cosmetic and is in the metal, not a film that could be wiped/cleaned off. No harm. Now, even with the ARX and subsequent GC use, I would expect to see at least some telltale deposits in the nooks and crannies if there was any "sludging", especially around the VANOS unit. Nothing. Bearing cap bolts? Nada. Cam journal castings? Zip. So is this the end all to the BMW oil debate? Heck no. But in this car, for 42K of dealer servicing (read: minimal), this oil did fine. I was able to contact the previous owner and he was very happy to answer my plethora of questions. Particularly about the oil service and his driving use/conditions. He said most was highway miles and he didn't "beat" on the car. Spirited runs, yes, but no flogging. I'll say it before someone else does, this probably has alot to do with the oil's condition. Even he claimed that had he driven more urban miles, he would have the oil changed at half (~7500 mile) intervals at his expense. Take this FWIW, but in this case at least, it seems all good.