The Mobil 1 15w-50 is good stuff but not the best (group IV oil), if you want the best then you are looking at an ester based synthetic such as the Silkolene Pro S 10w-50 or the Motul 300v 15w-5(group V oil).

Trouble with Mobil 1 is you pay over the odds for the "Mobil" name.

Cheers

Guy
http://www.opieoils.co.uk