When the Karma pulls onto the scales, the readout of 5,300 pounds is, well, accurate. In fact, the Karma makes the porky 3,755-pound Chevrolet Volt (as weighed by Car And Driver) seem like a true lightweight.
It doesn't matter whether it's the battery or the fuel tank that's providing the power, weight always reduces efficiency. In the end, at $95,900, the Karma is priced in a league all its own, and we doubt that many buyers will think twice about how much more efficient the Karma could have been. This thing's got other reasons for existing, like trying to make "green" stylish.
[ This post has been changed since publication.]