I bet they could make a wider front clip for road courses only. And for ovals reconfigure the car into a slim front end.

The purpose of efficiency is more for promotional value more than genuine contribution to green movements. That's only my opinion.

You know those CSX freight train commercials you see all over television now? Claims of moving 1 ton over 400+ miles per gallon of diesel fuel? I'm pretty sure that is pretty optimistic even at peak efficiency. That is, not taking into account starting off, getting up to speed, crosswind resistance, blah blah, etc etc. It's a great attention getter - but not reality.