I've been playing around with the lap times posted by Snowy and in particular the race simulations. I've been able to roughly align race simulations of Ferrari, Sauber Toro Rosso through when the rain hit. I think Force India's race simulation came earlier in the day. Produces some interesting results, though it is hard to read them all on top of each other.
The first thing you'll notice is Ferrari were going a lot slower than the Toro Rosso and Sauber. You'd have to assume they weren't running race fuel, perhaps trying to hide their speed. The next thing you'll notice, if you look a little closer, is the tyres degrade faster than the fuel burns off. All of the stints follow a similar pattern where the lap times get lower for the first initial laps while they are warming up, before the times slowly, but consistently get higher.
I'm hoping others will have some info on the tyres the teams were running, as i'm interested by the length of the stints by each team. Here are the lengths of each stint, roughly.
Ferrari 11, 10, 14, rain, 5, 8, 18
Force India 11, 11, 15, 11
Toro Rosso 15, 13, 12, rain, 13
Williams 12, 18, 21, 11, rain, 10
Also, average times of runs without rain:
Force India 1:29.4
Williams 1:30.5
Toro Rosso 1:30.6
Ferrari 1:31.3
Something tells me Ferrari won't be almost a second slower than Williams this season.