Drastic changes would have to be made to the body style to make much of a difference. You end up with jelly bean styling...aka the new GTO. The look of the new stang is what will sell it, not the efficiency. That is why the camaro isn't with us any longer and the stang is. Comaro got better mpg/hp because of the aerodynamic shape but looked like crap, so they couldn't sell as many as the v6 stangs(the real money maker for ford).