After some study, a favorable oil for our S63 is:
1. AMSOIL European Car Formula 5W-40 Synthetic Motor Oil Product Code: AFL
http://www.amsoil.com/catalog.aspx?GroupID=170
I will go with what the engine plate calls out (Use Only 07.51-0 002 545) not the 5W-30. I found out that the BMW 5W-40 was no longer available so the 5W-30 is an alternative.
Confirmed with my dealer, if I purchase the oil, they will put it in.
This is only my opinion, others may vary.
Cheers,
Lucabratsi