I have not tried without the bug guard yet. That was a purchase I made the first month of owning it. I really like the look of it, and I was under the assumption it wouldn't change mpg. The hood has a few dings from the previous owner that this covers up as well lol. I've been searching underneath the Jeep lately for places to maybe fab up some sort of aerodynamic pans or something. I have no skills in that area, though. I know they make a few skid plates for this model, but the owners haven't reported a change in mpg.