What is crazy is that when I ran around the block with it you could feel it was much lighter feeling and the air flowed through it as opposed to being a parachute like it is with tha back on and windows down. I wouldn't be suprised if the mileage did increase. I would say each door was around 60 lbs and a bit more for the back door.

And without the rear door, you can actually see behind you. It is nuts!!!

Of course, I plan to put 33" tires on it soon so that will negate the weight at least.