I read on a website about a guy with an M3 who says he will use nothing but Amsoil 0w-30 in his engine. His reasoning seemed sound. I was looking at their website and on their recommendation section for the E60 they have a stern disclaimer regarding engine wear.

It is my understanding that its a better oil than the stuff BMW uses (Euro formulation Castrol). Anyone use a different oil in their in-warranty E60?

if you want to learn about oil go to http://www.bobistheoilguy.com/ and you will see some info on oil.