[Brucelee]

Originally Posted by Paul

The lower the bottom number (0W, 5W) the better the oil flows at start up.

I believe this is the latest TSB from Porsche:

http://www.wrightune.co.uk/downloads/approved_oils.pdf

As a general rule, yes. However, to be precise, you have to check the actual viscosity at cold temp.

For example, the last time I looked, the Red Line 5w-40 actually had a lower cold viscosity than the M1 0-w-40.

That may no longer be true as these guys change formulas all the time.