Batteries are only part of the problem, and finding an easier quick change system. Getting a reliable speed control that can handle the huge power draw on full throttle acceleration is a major problem. It will have to be a ramp up power draw. A two speed transmission will ease some of this power draw. The other thing is weight balance and c/g. The batteries are incredibly heavy and the car will have much more weight in the front of the car. I don't see these cars really being as competitive handling wise w/o a suspension redesign.