Actually, you might also have to change out parts of your radio to make it capable to read dvd?
And though there are lots of these vehicles, very little of them have the rear screens. If you're able to salvage some seats, I'd try to pull the harness with it in case you need to route the video signal wires.
I don't think there's a Tech post on this swap in this forum yet. If you do yours, hope you'll share your experience.
*Disclaimer: I'm only sharing my opinion. You didn't pay for it, so my opinion is only worth that much, haha.<br />2013 GMC Terrain SLT-1, FWD, 3.6 V6 (LFX), Sunroof