Having tried the Coastal E Tech route and managing to destroy my factory NAV radio in the process (you have to take it apart on the '07s), I'm going to pursue the monitor-in-the-mirror approach now. I think the company that sells these is called Genntex or something like that... sorry I don't have a link at the moment.

Others have had successs with the Coastal approach, but a few of us noticed the clarity on our NAV screens (and audio too) had diminished by a notch or too with Coastal's stuff in the middle.

Genntex has an auto-dimming rear view mirror with a hidden camera image in it that lights up when you shift into reverse. It's about $339 I think and Coastal's hack-up your radio approach is only $229 or so. However, having to replace my radio for $500 (ebay) plus required programing at the L-M dealership has me wishing I had known about the $339 option up front.

Genntex (or whatever their exact name is) is an OEM supplier to FoMoCo and many others.