Steaming down the autobahn could be about to get a whole lot more efficient. Volkswagen has carted out its newly updated Super Efficient Vehicle concept, now dubbed the XL1, which -- after a great deal of fuzzy math, we're sure -- is rated at a 313MPG fuel efficiency and produces only 24g of CO2 per kilometer traveled. There's an electric motor and a TDI diesel engine making all the buzzing and roaring noises inside, while the overall body design is focused on making the car as light and as aerodynamic as possible. Vo
