Does weight really play that much role in mpg? I know Ive read from time to time about people lighten their vehicles and achieve X. I know on insightcentral and youtube Ive neen one of the higher if not highest mpg achievers with the gen 2 insight and I check in at over 6 ft and over 350 lbs. Infact I have to have a special office chair as I brake the ones that are standard issue or stretch them out of shape. Dont forget the 100 lbs of audio gear I carry to listen to loud music on top of that.
Still for a manufacturer to loose 700 lbs and keep all the bells and whistles is something else. I bet one of us could easily knock another 700 lbs off.