I used them on a Titan when pulling a 6,000# travel trailer. Mostly to level the truck so my headlights weren't useless. They worked well. Per the instructions I set my weight distribution hitch so the rear was 1" down and used the bags to level (40 lbs).
One thing to be cognizant of is some people with bags and onboard air will crank up the pressure while driving. This could have the effect of unloading the weight distribution and possibly anti-sway making for a poor and dangerous tow.
I put them on my current truck for pulling a fifth wheel with over 2,000 pounds of pin and bed weight. I have never needed them so they stay at minimum pressure all the time.
