[aerohead]

After winning the 1987 World Solar Challenge, Dr. Paul MacCready of AeroVironment ( partly-owned by GM ) who'd been a principle power behind the creation of GM's Sunraycer, and then the GM Impact ( EV1 ), commented that, with a modest ICE powerplant, Sunraycer would be capable of 400-mpg, and if the EV1 received, say, the powerplant from the Geo Storm, we'd be looking at 100-mpg. Something accomplished by GM the next year, when they unveiled their Ultralite concept, with essentially identical aerodynamics to that of the Impact.
It's been reported that, Sunraycer, with it's original full wheel-fairing package measured Cd 0.089 at Cal Tech. As-raced, without the fairings, Cd 0.125. Later Cd 0.143 ( wind-averaged Cd ).
For me, Sunraycer has remained an inspiration, and my reason for exploring a 'gapless' tadpole trailer combination, to take advantage of the lower spectrum of drag.
If Cd 0.089 holds, this would be one corroboration of Wolf-Heinrich Hucho's 1987 comment about the technical feasibility of Cd 0.09 automobiles.
Which makes 200-mpg less of a 'reach' especially in light of electric drive.