Very easy install on a 2016 Low Roof Sprinter 2500 with after-market rails (VanTech). Took less than an hour to get to get the side and cross bars set-up. No special expertise or skill required: if you can screw a bolt in, you can do it. Was able to fit 2 Newpowa 175w solar panels vertically in front with about 1/2" to spare across (max width between the rails is about 53 1/2"). Not only did they fit the panels but they are also flush with the top of the rack. One nice feature of the rack is that the 6 rails, which you can mount almost anyway up and down the rack, are 10-series 1x2" 8020 aluminum T-Slots so you can use whatever 8020 compatible fasteners, hardware, panels, etc. you want to easily create a custom set-up. For example, I mounted a Road Shower 4 across the back, which fits with about and inch to spare, by attaching some small 15-series 8020 crossbars to the rails. I also ordered some custom aluminum plates from 8020 and was able to fasten them directly to the rails creating a nice walkable roof deck/tie down area. The solar panels were also fastened directly to the rails by using 8020 compatible hardware. The rack has attachment/mounting holes down the outside length of the rails so you can easily attach things like antennas (I attached a SureCall cell booster on one side),awnings or whatever. Net/net, not sure why one would pay $3 or $4K for one of the "custom" roof racks when you can buy this rack for a lot less and very easily customize it yourself in whatever configuration you want.