The fans on my motor give me more than 10 degrees celsius advantage. Even more, I think.
It only cools one side of the motor, but heat is conductive. Some smart guy once told me: Daf, if you heat a piece of metal on one end, it gets hot on the other, too.
Getting rid of heat is a good idea, but it's even better to choose a setup that's not too "close on the border".