Hi, just out of interest, which Android head unit did you get? Would like to do the same, but would like some first hand experience?
I looked at many different units, but chose this one:
Eonon G2110ZV | Car GPS | Car DVD GPS | 2 Din Car GPS DVD | Android Car GPS | Android Car DVD Player
I know it's a cheap chinese model, but it works really well.
Only thing I've had some trouble with until now, is the BT adapter I've got in my OBD. I'm using it with the program "Torque", which is a super cool tool imo. I can connect to my phone, but not my headunit, so I'm working a bit on that.
Other than that, it works really well. I've got a 3G USB dongle on it, so it's always online. I use Google maps as navigation when I'm in Denmark, if I drive to Germany or other places, I use an off-line navigation program. I just download the maps I need and it works perfect.
BT to phone works perfect, both calling and music.
It just works, I'm happy with it so far.
I did look at the Parrot Astroid a lot, but I don't know how to Root a unit, and I wanted Google Play as an option for downloading apps. And the Parrot only uses the Astroid market .
So, hope that helped, and just ask if you have any questions, I'll do my best to answer them, just have in mind, English is not my first language, so there might be some misspelling :-)