Like John says - the factory unit (Voyager) has a wireless antenna on the nose that transmits to the truck. You see on some folks pictures - its a round bump (like a wart - for lack of better words) that sticks out in the center of the front cap.
Installing the wiring like the factory did is a bear I believe. Its hard to get the wiring down the back clip to install like the factory (Mudchief did this) and probably harder to get the wiring up to the front clip for the antenna. It would take some creativity.
The cameras look like a great option, but I've never heard anybody make comment on how well they work (Factory units).