Or if you want to keep the OEM stereo, you can get this mirror instead

New Car Rearview Mirror GPS HD 720P DVR Built in Radar Detector Parking Camera | eBay

It has Bluetooth, GPS, rear view camera, front camera with DVR, music & viddo player and can send audio to your radio on an unused FM channel in your area.

It also looks like a simple installation. I might even consider it myself.