2007 DVD player question?

My sister just bought a 2007 Tahoe and it is the LT package and was wondering about installing a dvd player in it. I found the DVD head unit on ebay for $350 but couldnt find the screen. Has anyone ever converted these over with the factory parts and are they already wired for a switch? Thanks for your help. I have a 2007 Tahoe as well with the z71 package that has the dvd system so any help. Would think it would be simple but you never know...