I'm also thinking of replacing my current tape-only Mercedes-Benz Special head unit with a Bluetooth and iPod compatible unit as we are going to be using the car quite a bit more than previously.http://i.imgur.com/ERHbSaE.jpg
We use Google Maps on our iPhones for navigation so it would be handy to have it coming through the speakers as it does on our other car.
This seems a good place to start.http://thewirecutter.com/reviews/best-bluetooth-car-stereo-receiver/
The current MB unit sounds surprisingly good considering how noisy the car is (diesel).
Other issues: [a] the volume knob sometimes goes louder/ quieter when I turn it to do the opposite.
[b] both speaker grille covers in the back doors are broken (kids pushing the doors open with their feet). A0008202812