As with everything else, it all depends on where you're at and where you go. I'm out here on the Barbary Coast town of Baghdad by the Bay. Believe it or not, nobody has the "franchise" for Line-X in The City. I have three local dealers. They gave me three different prices......for the same truck!! The difference between the three quotes was almost a hundred dollars.....for the same truck!!
I recently had my Line-X applied and was allowed to watch the entire process. I am impressed. I love my Line-X. But I'm not in any sort of building trade, nor do I do any hauling. I'll never be able to say with any level of certainty just how good or bad it really is.
But according to National Research Council Canada,
http://www.nrc-cnrc.gc.ca/highlights...uplands_e.html
"While lowering or removing the tailgate on trucks with an eight-foot long box may decrease the drag by a small margin (less than one percent), lowering it on a six-foot cab – like those typical of crew-cab trucks – increased the drag by five percent. Using a mesh tailgate cover raised it another five percent or more."
I'm reading that with an eight foot bed, which I happen to have, lowering or removing the tailgate decreases drag. I have an eight foot bed. I drive with the tailgate off. Why? Because the rear of the truck is so high that I never see anything but my tailgate when I look over my shoulder. It's great to see a little more of the road and who or what is on it. But living in The City, I like to be able to see all the little Hondas when I'm parking. I have actually parked in spaces where some lowered import ended up with my bumper sitting over his hood.