I am actually getting an advent system installed this weekend. The headrest are factory replacements for the current headrest in the truck. As far as I know, there is no integration into the head unit. Comes with two IR headphones and two remotes. Also, installation is rather painless from what I have been told. Here's a link for info on the headrest.
Also a YouTube video demoing the units.
They use the factory leather codes so that everything matches.
Hope this helps.