Hi guys,
I live in China for long time now and I have A200L (long wheelbase model for China market). This carplay/android auto full screen problem was already been solved in China for some time with something called Baidu Carlife.
Its a system similar to carplay but it takes over your whole screen somehow.
My car have this turned on by default together with carplay and android auto. (in china this comes standard)
So there is this wireless small box that connects trough usb-c port in your carplay/android auto plug. Then you connect to the box with your phone trough wi-fi and blutooth (yes, both) and full screen apple carplay appears on your screen.
Direct apple carplay with usb-c cable is only supported in that stupid container box in the middle of the screen.
Like this with this box you get full screen.
Weird thing is that in the media on the gauge screen I get the message that controls for media are unavailable since android auto is connected. So I think this thing works trough android auto protocol somehow.
So you cant control your carplay music using left buttons on the steering wheel (right buttons in the UK I guess as your steering wheel is on right hand side)
When I try to connect it trough android auto tab, same carplay screen appears and its again connected as baidu carlife.
Its a bit laggy since it works trough wifi but its pretty stable. You enter your car, turn on ignition and carplay appears in 10 sek.
Small issue is that seems you cant get to carplay maps or music screen with shortcut in the middle console (place where are radio/media, favorites, park assist etc...). You need to use touchpad in the middle console or touch the screen.
So Im not sure if this will work in a-class (or any other mercedes) for euro/uk markets but you can see that limitations are not so great that you need to replace whole unit that connects your car's vital functions.
I have to say that resolution is not crazy crisp as mbux but you cant really notice it unless you are very very close to the screen.
You might be thinking where is climate temperature or AC setting now when whole screen is taken by carplay.
Well, when you adjust your temp, temperature tab will appear and then disappear after few seconds. Mercedes could do that at the beginning and not limit people to this tiny container in the middle.
If you have any question I will be happy to answer since I was also looking for this solution long time before.
Cheers