[Overdriven]

For slower speeds, four wheel steering would probably help out alot.

The thing I worry about with thrust vectoring or a traditional rudder is matching how those want to turn the car compared with how the wheels want to turn the car. With these systems I picture the rear of the car being pushed sideways instead of actually turning the car. To ensure better steering at higher speeds + thrust levels, I think a rudder mounted over the front axle would provide the best and most natural "feel".