Well I lowered the new truck on the weekend and put air bags in it, I like the way it sits much better. The truck box rails now sit at the same height as my old 2017 this coming weekend I am going to hitch up to the 5th wheel and see where I am. The hitch is sitting about 1.5" lower below the rails then it was in the 2015. I think I will 1.5" less of box rail to 5th wheel clearance so I should be right @ 6" I was at 7.5" before.