We know that, and we know that it is a superior oil, but what we don't know is if it's properties have changed such to make it now unacceptable to use in a wet-clutch application.
Mobil 1 Extended Performance was just made available 2/1/05. The Gold Cap is better than the Red Cap because, amongst other things,
The old 15w50 redcap was just fine, although Mobil would have us us only MX4T or V-Twin (at $10/qt from a cycle shop).
Personally, I'm switching to M1 Truck & SUV, probably for my Tundra as well as the bike.