The advantage of the factory system is that it's not only a GPS, but also has the fuel consumption, recharge, energy flow displays. If I were looking at purchasing brand new and had to have the NAV that would push me towards the factory system. But I would not pay $1800 + installation off ebay for a factory unit.

Actually my wife asked me what I want for ChristmaKwanzaNukah. I told her a portable GPS. She asked me why I needed it as I never get lost. Even when we're on long trips and there's a traffic jam on the interstate I seem to be able to get off, take local roads for an exit or two and get back on after the traffic jam. I eventually had to admit I like having toys.