I have just finished installing the ShowBoat on the car and have only loaded the boat once for practice. I would have liked two stop collars instead of just one. The driver side bar wants to slide forward more and I have stretched the bars out to max allowed. So far I think the unit will protect the rear edge of the back door of the van just fine. It is just long enough for the Sienna Mini Van - it barely covers the area needed, but the kayak will not be in contact straight up and down. I expect the rating could be a five once I have used it a while.
2015 Toyota Sienna dual door