But if your car is not unique it could make sense to share it.
However if you are interested in doing it I can give you assistance in greater detail let me know. Also, it would be great to see if you can get v81 apk to decompile but Ive had no luck with the latest apktools- it throws exception trying to generate the dex (smali).
I would be interested what's the best way to replace the existing MainUI.
a) install it as simple update by clicking on the apk?
b) replace the apk on system partition? Is this possible while system is running? Chmod required afterwards?