Believe it or not, there are 2 5W-30 synthetic oils on the approved list. However, they are oils that are not sold here. I agree that European car companies are more interested in engine protection than fuel economy. You will be hard pressed to find a European engine that calls for anything less than XXW-40. My VW Passat calls for 5W-40, and only to use 5W-30 if 40 is not available. I use Valvoline Synpower 5W-40 (A3 rated) For a good conventional oil, I would go with Castrol 10W-40 every 3K, for your V-8.
1994 MB E320 Coupe (199,500 mi)
1992 MB 190E 2.6 (173,000 mi)
1983 Porsche 911SC (148,000 mi)
2004 Volvo V70 2.5T (198,000 mi)
President of CT/Westchester Section