Oil is very confusing. Only recently I read more about it and it seems the thinner it is when cold the better. Although for example Castrol's 0w40 is actually thicker at 20C than their 5w30. There was an article somewhere about it and how most oils are too thick below 50C. Ideally they would be the same thickness as at operating temp.
Also lots of discussion on bobistheoilguy about ester based oils like Fuchs being better than most other synthetic oils, but they are expensive. I just use Castrol Edge 5w30 and hope its ok.
I remember watching a mechanic pour Castrol non-synthetic oil into my old volvo, it was the consistency of honey. Only now do I know that is not good.
If one was really obsessed about minimising engine wear, oil should be warmed up with something like a Wolverine oil pan heater before every start up.
Here is that massive article I read. Hopefully this doesn't say anything misleading.
http://ferrarichat.com/forum/faq.php?faq=haas_articles
Interesting chart here, showing just how much more viscous Mobil M1 oil is at a warm outside temperature of 20c its not even on the chart, compared to its viscosity at operating temp.
http://www.bobistheoilguy.com/forums...Number=1956279
Just one more thing... came accross this, some used oil analyses of castrol edge 5w30 sometimes come back on the thin side closer to a 20 weight oil. Not sure if this is anything to worry about?
http://www.bobistheoilguy.com/forums...Number=2290490