I had the regular non-screen CD/radio/XM head unit in my '08 and switched to a 2010 nav unit for the touchscreen, USB and backup camera functions.
I didn't know they had units with DVD and no nav- is that what you have but are looking to have the same features plus nav? I don't know about the 2012+ units, but at least on my 2010, the nav kinda sucks as far as using it. I'd much rather use a Garmin on the windshield.
I second Dale's info and recommendations. It's difficult to find a dealer that's experienced and knowledgeable enough to successfully program a head unit. I've read of too many horror stories of it not being done properly and even head units that were "bricked". The safe and surefire bet would be to have Greg do it.