This is one of the best articles discussing oil temperatures, viscosity and weight.
Cliff Notes: We need flow not thick viscosity.
Oil temp range determines pressure and viscosity.
Cold start up is toughest on wear.
Our filters by-pass on cold start up more with high viscosity.
http://ferrarichat.com/forum/showthread.php?t=136052
http://ferrarichat.com/forum/showthread.php?t=136052