I understand that the 40KWh and 85KWh variations of the model S weigh the same due to the model with the smaller battery having some added ballast where the missing battery packs go in order to simplify the crash testing process. Once a car is delivered, I wonder if removing the ballast would be possible. According to my calculations, 45KW of battery should weigh about 800 pounds. Saving 800 pounds of weight would do wonders for acceleration (maybe getting the standard model S into the 4 second territory, simple math would put the car at around 4.7 seconds in 0-60) and save some gas. It may even help with handling (though that, I don't know). Of course it all depends on: * if the battery pack is accessible without disassembling the whole car. I guess yes since it should be replaceable. * if the 40KW pack is centered on the car. If they just left the rear of front pack and removed the rest, then removing the pack might upset weight balance, though it might also help, it depends on how the balance changes. * if the ballast is a solid block that can be removed (and I guess replaced with something innocuous, equally solid and lighter). Does anyone have any ideas on this? This could be a very straightforward "tune" to do to an already fast car. I'm betting on an aftermarker "upgrade" in the form of lighter ballast.