Well, as a tribute to the power of marketing, I could not convince my co-worker that Mobil-1 5W-30 was an ok, but not optimal choice for his 2000 VR6; This despite providing 2 PDF files that came directly from Volkswagon One PDF explained the 50x spec appropriate for his vehicle and another showing the oils that meet the spec (0W-40 on there, 5W-30 not) I also C+P'ed directly from the Mobil-1 website showing the "European formula" 0W-40 oil that meets numerous GERMAN specs and how the 5W-30 meets none.
His friend that owns a VW shop told him M1 5W-30 is "the best" and he wants "the best" (3K changes too...) for the Jetta.
The written word apparently has no power over perception.
I'm tempted to buy some GC for him, but I'm not convinced that it wouldn't end up in the garbage.
Not sure how I get 8K-10K miles OCI on my car and I don't use "the best"