I've known about this.
I remember seeing the video of this record being achieved:
If the production car were this slippery, it would have needed roughly 100 Wh/mi to do 70 mph on the highway, and would have been a 150 mile range car with the Panasonic PbA batteries and a 250 mile range car with the Ovonic NiMH, at least on the freeway, without drawing the batteries down too low to the point of damaging them. City driving range with these changes versus the original wouldn't have been impacted much, but it is highway driving where long range matters most anyway. The production model needed about 150 Wh/mi to do 70 mph on the highway.