I have the Honda tip out full windshield and Honda roof on my 500, along with the plastic rear panel. Like I said I've towed it 1000"s of miles. One of my best friends has a cabin in south central Colorado and it's just a little over 1000 miles out there. We pulled it once with my 1/2 ton Ford on my 14 ft trailer. Once we hauled it in the back of his 3/4 ton diesel Chevy and twice we pulled it on his trailer with his truck. The CO trip is 2/3 f interstates and all but the last 100 miles is flat straight 2 lane roads. We've tried it with windshield and back panel out and with them in. I've checked the mileage several times and I actually get a little better mileage with the windshield and back panel in than I do with them out. With my 1/2 Ford, 5.0 motor, it was 1 mile per gallon better on flat ground, freeway driving. 14mpg vs 13mpg. I've checked this several times and it's always come out the same. I've never checked it in the back of the truck with the windshield out, as the only time I've had it there was the one trip and we had the cab of the 500 packed with stuff we didn't want to get wet. It's 75 miles from my house to our deer camp, two lane roads all the way and hilly, I make this trip at least every 2 weeks, always with the 500 in tow. I've checked the mileage here too and there's no difference in the mileage. This trip is slower, with the transmission in trailer haul, with lots of hills and curves, so the speed is a lot slower. I've stopped checking now, the windshields stay in for me. One thing, I've never towed or hauled the 500 backwards. That straight up back panel might make more of a difference than the sloped windshield facing the wind, I don't know about that. I've owned my 500 since July of 2014, we've made lots of trips together. Anyway, good hauling, hope this helps.
