I don't know of any 2d physics libraries with decent top down support, esp. in Java - Box2d (and once I port the changes, JBox2d) has this planned for a future release, but it's not going to be in for a while.
BorisTheBrave has a controllers framework with a tensor damping controller (see http://www.box2d.org/forum/viewtopic.php?f=8&t=1567&hilit=controllers
), which might be useful for some
top down stuff, but I haven't ported it to Java yet, and I'm not sure that it would do everything you need. I still haven't played with it myself.
I agree with Orangy Tang, though - for a racing game, you probably want to really
micromanage the car behavior. You may be able to do this within a physics engine by applying forces and torques, or you may want to write your own mini-engine for it, but you probably don't want to just rely on the default behavior that someone put into an engine, because tuning that stuff for the desired feel is absolutely critical for your game.
Edit: someone put up a Flash demo of something like this using Box2d, see http://www.box2d.org/forum/viewtopic.php?f=8&t=1547&st=0&sk=t&sd=a&start=0