In my 4.5 i stick with 10w30 or 40.
I found 20w50 WAY too thick and I wouldnt think of 5w30 in an engine I drive that hard and gets that hot.

I would go with 10w30/40 in any m116 or m117. People tend to put in thicker oil in these and it winds up putting a lot of sludge in the cam oiler tubes, cutting off vital flow.