By taking off the lift jacks and installing the airfoil pictured, I gained between 1.5 to 2 mpg. This is above the 11 to 12 mpg I was getting. mileage measured with a Scangage II
It's bolt on. You can see in the pic where the clamp is, it's just above the front door. There is a bracket attach to the load bar and the faring attach to that bracket. The bottom of the bracket has foam pad and is resting on top of the roof. I put some clear rubber foot on the roof to prevent the foam pad from rubbing the paint.