Why do you think the contact patch changes size at different speeds ? The vehicle still weighs the same amount no matter how fast you're traveling, and can actually weigh more from downforce.

And what car weighs less than 2000 lbs ? The Lotus Elise is the only one I can think of. My WRX weighs 3000. And where did you find a 3000 lb. F-150 ? Ford says they weigh 3700.