I have contacted FWC about the install of my Eagle on the new Colorado (diesel)...have to raise it about 1.75" to be over the bed side rails. I have seen both horizontal and vertical "2x4" additions to the base to raise it. Is there a benefit either way I am missing? Any experienced advice about method as I know they use stacked ply strips to boost the height (and they go horizontal). I was thinking of perhaps using pressure treated 2x4 (1 5/8" x 3 1/2") and running them vertically so that I could install perhaps a drain pipe for grey water tank to the back. Though not completely related...is there a problem with removing a lift assist tailgate?