Both numbers came from the Elio team. Figuring a 200 pound driver, the 1800 pound (1600 lb. vehicle/200 payload) P5 getting 81 MPG should easily make it's targeted 84 MPG at 1400 pounds (1200 lb. Vehicle/200 lb. payload) In fact, at 7/9ths the weight, it might approach 90MPG. (less weight, but the wind displacement is roughly the same.Where do people get the idea that they are packing an extra 400 lbs? That would be an awful lot of weight to pare off what I thought was already a pretty lean machine. If they are getting 81 mpg with a 1600 lb trike 84mpg should be a piece of cake with a 1200 lb machine. Larry