You will really like that fold down rear seat. I put one in my 'Burb and love it. It was a pretty straight forward install. I made some panels to hold up the back and welded nuts to those. I had to shim up the bottom of the seat on the outside edge IIRC. The "piano hinge" bolted down on the nose of the step down.
The only draw back I have is having to slide the front seat most of the way forward in order to lay the rear seat completely flat. I got short legs though so its not really a problem.