The biggest problem with turbine powered cars was coupling to the wheels. Turbines have two unfortunate properties that make them very unsuited to directly driving the wheels of a car:
1) They spin far too fast, so you have to have a transmission to slow that down.
2) they don't like to slow down too much, so you have to have some means to clutch them so starting from a stop won't stall them.
In applications like helicopters, that's not a big deal: once you have the rotors turning, you'd like to keep them turning.
But for cars it was a deal-breaker.
I highlight was because there is a better idea on the block:
http://www.capstoneturbine.com/prodsol/solutions/hev.asp
The idea Capstone has is that you have a single spindle turbine, with a generator on the same shaft as the turbine. There is no mechanical coupling of torque to the wheels - the system makes electricity. That works well with an electric drive train - electric motors have no problems with making torque at zero RPM, they have a wide torque band that reduces or eliminates the need for a transmission, and the turbine can be started and stopped as needed to maintain the batteries. The Capstone turbines don't need lubrication as they use air bearings, and they meet or beat all the air quality standards on the books or planned to be on the books, running on diesel.
I just hope somebody gets smart, and makes a van chassis on this tech, with different bodies for Suzy Soccermom, UPS, Class-C motorhomes, and basic transportation, that uses heat pumps + resistive heating for climate control (so that it can run off the traction battery without needing to run the turbine to make heat), and that gives me access to 120VAC@50A from the traction batteries (plus an inverter, naturally) so that I can use it for camping as needed.
(no, I neither work for nor own stock in Capstone - I just think this is the way things need to go.)