[donv]

I believe you read oil weight/viscosity ratings as:

[flows like a] w [protects like a] , so...

0w40 flows like a zero single weight oil and protects like a 40 single weight oil.

If I remember correctly, the manual recommends up to a 15w50 for warm weather and down to a 0w30 for cold. Under the above reasoning, a 0w40 would be "better" in terms of protection for cold weather and still meets the cold flow requirement, therefore I wouldn't be concerned particularly about revving to redline in cold weather with that oil.

What I find interesting is that most dealerships seem to be using the 0w40 as their standard weight (a compromize "all season" weight), which would seem to mean that in warm weather some protection is missing... I have been using the 0w40 myself but decided this year to switch to the 15w50 at the next change given that the car 'sleeps' for the winter anyway and so I don't need the zero weight low end but could use the warm weather protection.