help needed! scripts for "bump & jump" type physics (Unity3D)

[headcaseGames]

Hi all, making a top-down racer much like this one where you steer a car, and can jump (crash down on top of other cars, etc). Whereas the one shown is 2D sprites, ours is 3D (Unity Engine) and involves a bit of physics. I am not the tech guy but I am supporting the coder; could someone point me in a good place to start looking for the type of tools we'd need to download (free or purchase) and adapt for this specific purpose?

Essentially, trying to keep it light (not very physics-heavy) but of course it does need to run in 3D and it does need to do what it will do (driving, bumping, jumping) properly. Thanks for your help!

I posted this link in unity forum as well (scripting section) as well, but I figured it would probably be at least as useful to ask on this forum as well.