Why not get a headunit thats the same size, with a flip out screen display. Navigation that you can see is a lot easier than simple voice prompt. I rather see a map of exactly where I'm going. Sometimes you mapquest stuff, and it gives you some very uneccessary instructions, which could end up being a pain if you only hear them, but have no idea where your truly going. Plus with a flip out screen you could put a DVD player in your trunk or somewhere else, and use it for more than just navigation.