Update: I have it working, but it's only with stereo audio currently.
I have somethings on order to see if I can get 5.1 audio out of it.
The official 7" screen works fine, but the border makes it so it won't fit in the center stack.
so if you want this with the official screen, it maybe a good option for the top section.
You can load android OS on a raspberry pi.
Some question I had that you may have:
1. boot time.
it take about 30 seconds for it to fully boot.
But at idle it draws about 230 ma and so the screen draws more at idle.
The screen can be disabled when the car is off. Same with the attached usb devices through a powered usb hub.
So, the computer can be left on while the car is off for maybe a few days to a week.
There are some scripts that can power it off when the car is off, so say if the car has been for x number of hours, it will shut off, and power up when the ignition is on.
I probably do this, so I won't have to wait for 30 sec for it to boot every time.
An additional radio module would be needed, but not recommended because it taxes the processor.
The alternative is iheartradio through the phone, if your preferred stations are on there.
3. Connecting the phone.
You can connect it to it directly, but I recommend plugging it through a powered usb hub. Directly, it draws some mA from the pi causing the cpu to clock down to keep stability.
You can connect it through wifi, and have the phone charging from a different charger. I haven't played with this too much yet. You can stream ad2p audio to it.
4. reverse camera
You can have it trigger the camera from a pin on the board. Since what I have played with, a few years ago, the pi cams are fine, but I want to use a usb camera, as mine have auto focus adjustments.
I haven't messed with it yet, because I have just been testing what's there right now.
Since on the subject of raspberry pis, I was thinking about messing with the pi compute module 3 and see if I can accomplish the same things as using a normal pi 3 b, without having to buy additional equipment.
So having a custom carrier board made with everything on it, and then just slotting a CM3 board on.
It it works then you would just need a CM3 board, a touch display, and maybe a harness. Possibly having a second CM3 board to offload the computing for a FM module.
Just some thoughts I've had while messing with this.
Posts some questions so I can test things.