Originally we were going to do a rear-view mirror with a built-in screen....but after some investigation, the factory mirror had 2 mic's built into it, as well as a few other items....so that's a No-Go.
PAC-AUDIO to the rescue. Used their Back-up camera interface unit that allowed us to tap into the factory 5" screen and made it function just as intended and like it came from the factory.
Then we put in our Omega remote start module that integrates into the truck without knowing it wasn't there in the first place!