Kubica will be their Friday driver. With his experience and feel, most likely he will be setting up the car for a rookie and the money kid who was a rookie last year. Williams gets all the money, plus someone to set up the car. Kubica will get to work on his speed, and see if he has what it takes to be competitive again. As for all circuits, wheel to wheel, etc., one can only tell when that situation arrives, or not.
As an outsider, Williams appears to be chasing the pay money drivers. I am not expecting that they will have the greatest season, even though they have the best customer engine. I expect Force India will wipe the floor with them, with their fast pilots. Even if they crash into one another once in a while.