Is it possible to make the car scrape against barriers and other stationery obstacles like in Ridge Racer? It currently bounces or just stops dead, turning more toward the barrier no matter which way you steer. Using the usual rigidbody and box collider for the car (as seen in the tutorial) and mesh colliders for everything else.
In the standard assets there's a folder called physic materials. Have you tried applying the "Ice" one to your colliders?