As anyone who’s ever participated in bench racing will tell you, it’s easy to throw down numbers and brag about specs from a sheet of paper. Backing numbers up with real-world performance, on the other hand, can be a bit more difficult.

Take Jaguar’s uber-exclusive, million-dollar plus C-X75 supercar, for example. Originally, power was to come from microturbines, which in turn would drive a range-extending generator to feed the car’s on board batteries and power its electric motors.

Since microturbine technology is still in the developmental stages (and that’s being optimistic), Jaguar recently announced a change in powertrain technology for the C-X75. Instead of microturbines, the car would be powered by a 1.6-liter four-cylinder engine, capable of producing over 500 horsepower via forced induction.

The direct-injected, turbocharged and supercharged engine would send power the rear wheels, working in harmony with front and rear electric motors. While there are provisions for a full electric mode and a hybrid mode, there are no provisions for a pure gasoline-powered mode.

Jaguar claims that the C-X75 will sprint from 0-60 mph in under 3.0 seconds, on its way to a top speed of over 200 miles per hour. In electric-only mode, its range of 37 miles will be similar to the Chevrolet Volt, while the 0-60 mph time will take a more reasonable 6.0 seconds.

Before Jaguar Land Rover will give the official green light to produce 200 copies (at as much as $1.4 million each), Motor Trend says the automaker needs to make certain the car will live up to its billing. Five validation prototypes are under construction, so the fate of the C-X75 rests on their shoulders (or in this case, roof pillars).

While the “business case” calls for 200 units to be sold, if demand is higher, expect production to be upped. What’s your take? Is there a market for another high end plug-in hybrid supercar alongside the Porsche 918? Can Jaguar sell 200 units at over $1 million each, or will that quantity not be enough to meet demand?