Finished fitting mine today (ignore the plastic on the screen, I promised my partner they could remove it!)
It works really well. The only thing I don't like about it is once it's booted it makes a god awful chime that can't be turned off (which
can be heard here). I will probably physically block up the speaker holes or disconnect the speaker if it continues to bother me.
You can update the boot logo to something more suitable by putting a 1600x600 pixel jpeg called "boot_logo.jpg" and a zip of it called "boot_logo.zip" onto an SD card and plugging it in when the unit is powered on. The process is described in more detail in the comments of
this reddit post.
I made a simple one.
To power the screen I used a generic 12V to 5V 3A USB C converter and plugged it into a switched 12V accessory power cable. The USB C cable comes up behind the hazards switch and between the vent and dash (you have to at least partially remove the vent to do this)
I wouldn't recommend using the radio broadcast function for audio. You could use any Bluetooth receiver plugged into the aux.
I used one of these that you plug in behind the radio, unfortunately the Bluetooth receiver is powered by a wire that is constantly 12V even when the car is off. So you will have to cut that wire and also use it with accessory power.
I designed a little mount for it in fusion 360 and got it printed it in ASA, It uses the spare adhesive pad that the screen comes with but the curve isn't perfect and I'm not sure how well it's going to hold. I've bought some 3M VHB tape to try and mount it a little better.
I put it on thingiverse but new accounts can't add anything for 24 hours, I'll post tomorrow with a link.