I've got the 8100 X-Cess 5W-40 in my VW 1.8T right now and I'm very excited to have found a G4 5W-40 that meets all VW requirements (especially the 5W-40 part) and is API SL. I've been running it for about 1000 miles.
The engine seems to run smoother, though I don't see how that could really be the case, and the local import shop (both mechanics drive VWAG products) was really intrigued with the oil when I brought it to them. Anyway, the idle, never bad, is unusually rock-steady while this oil happens to be in there.
This oil does not smell very good, however. So if you keep some in the car with you, it won't be a very pleasant traveling companion.
Despite being '5W' cold starts (between 20F and 32F) seem to take a little bit more cranking effort, like when I had some Mobil 1 15W-50 in there during the winter. It's also an unusual orange color.
I've ordered a kit to do a UOA, so maybe I can offer something more factual about it later.
[ December 11, 2003, 01:50 AM: Message edited by: 1781cc ]