Imagining a new car

Start with a Tesla roadster or sedan. Take out the transmission. Take out 90% of the batteries. Replace the wheels (keep the tires) with regenerative braking electric motors. High torque in the rear and high speed in the front. Add a generator directly driven by a Stirling motor. The heat source is a small self contained thorium/laser unit that you replace every twenty years. You have about 400hp. Add a computer to manage it all.

If you prefer to refuel every 200 miles you could go with this...