I finally had a chance to install it yesterday, no pics yet, but soon. A couple of things. Mine did not come with the foam spacer block to make sure that the drain rails were the proper distance. However, I did my best and it seems to be okay. I am going to contact Extang to see if they can send me one so I can just double check.
Other issues: 1) The latches on tailgate section are very hard for me to get to actually latch on. I really have to slam it to get them to latch. The drain rails are level, I tried adjusting the latches in/out and nothing changed that. They do latch, but I really have to slam it shut. 2) No rain yet, but even with just a heavy dew overnight there was some water leaking in from the back corners by the window and the corners by the tailgate. Seems like an easy fix would be to just put down some thin self adhesive weather stripping in those areas. 3) Seems like the seal on the tailgate sits just on the very very edge of the tailgate towards the inside. However, it does look like there are three lines of seals on the cover and that they may create a barrier as it didn't seem like it was leaking there.
Overall though, I like the looks and functionality of it. We'll see if I can fix the slight leaking issues. I didn't finish installing the drain tubes yet, but I think I will just enlarge the holes that are already in the plastic bed cover and stick them down there.