While I was doing research on adding a navagation unit to my 2011 Travers LS, I came accross alot of threads on this forum. So I decided to share my results from doing a factory navigation unit upgrade. I found that the GM radio that worked best in my traverse was GM part number 20792736. I chose the 20792736 for my install for due to it supports the rear dvd systems (just incase I decide to add that in the future). I also had to add the GM facotry GPS antenna part number 15201798. The GM nav disc that was needed for this install was 20945286. The radio came brand new and pre-programmed from schram auto parts (check ebay) and the complete install took me less than 45 minutes. As far as cost goes it will from from $600 - $850 depending how how you get your bundle. This unit is an orange lite unit and so far the door chimes, onstar voice, music, and nav voice all sound like they are playing at the proper volumes. I have lost the sound of the turn signals for some reason but that is not a huge deal to me.
I used a plastic knife to pop out the dash trim piece
The trim piece removed
Pop out the trim around the radio by pulling with your hands
The trim piece removed, next remove four bolts.
The wire connections on the backside of the unit
Unit fully installed
Please note I did not take pictures of the GPS antenna installation , but most of that is the same from outlooks, arcadia, and traverse. However I was able to install mine without removing the handle on the passenger side.