I don't drive much 100-150 miles per week

... a humble opinion from Pittsburgh.

5W-30, or 5W-40. But--it also says the oil should meet ACEA 2 or 3 standards. As best I can find so far, only Castrol Syntec 0W-30 (Euro formula) meets ACEA 2 or 3 in the prescribed viscosity. Any other thoughts?

I found that my S6 engine was far more prone to lifter clatter on cold start up (after 3 or 4 days of nonuse) when using it (as opposed to the European Castrol). My car often sits for extended periods so I am somewhat concerned about that. I actually ended up draining the Amsoil and going back to the Castrol a few hundred miles later just to deal with that. My only real thought I guess is that there seems to be more to motor oil than just the numbers. Maybe it has something to do with the VW 502.xx spec (which the Amsoil did not have) but given the latest Audi recommendation on 5W-40s, I will probably try the Castrol version of that on the next round.

I've had great luck with regular supermarket variety M1 5W30 in the 2.7biturbo, whcih is a more demanding application by far than the easy-going 4.2.

That said I use M1 0W40 now.

Several industry engineers I have spoken to all feel M1 is about the best - this is Mobil's competition talking, over beer. I would not assume that smaller firms like Amsoil or Redline are superior. In fact the published specs on thisngs like flash point and shear index are inferior, last I looked.

Grant

Has any one had high oil consumption? 60 total miles. 4 quarts in 2500 miles