Maybe there's some fundamental misunderstanding about the physics engine. You posted many times here with always similar problems. Please understand two things. We haven't made PhysX and can't fix its "bugs". And what you've told does not sound like a bug anyway.

Physics engines are not perfect, and problems like jerking wheels on low-poly ground are typical and must be addressed by the game developer. We've provided a simple car and a demo to show how to use it. You can just make your game from that demo and won't have problems with jerking wheels. But if you're more ambitious and want more realistic car behavior, you're free to create you own car, maybe with ball joints for the wheels as in ODE. But then you have to dig into the matter and address the same problems like any other game developer who uses car physics.