Call Crutchfield, they will know for sure.

I did this for a Toyota using an idatalink and retained everything plus added a few things. the idatalink translates the cars information into something a compatible head unit can understand.

TPS, oil, water, check engine, steering wheel controls, etc. some vehicles even have climate control and window controls which are supported.

Coming from VW/Audi it’s easier to just grab a factory unit and have it programmed. Yea it’s expensive, but the German cars aren’t super easy to tinker with.

Good luck is my best answer.

You'd have to find out exactly how each subsystem works, and reproduce that to the extent it's provided by the factory head unit.

Take the TPS - how much of that system is integrated into the factory unit, or does it just display data retrieved from the TPS system? If it just retrieves that data, how does that interface function? Does it run over CANBUS, or does it use a point-to-point connection with custom signaling?

You'll have to figure this out for everything controlled by the head unit.

I really doubt this is a realistically achievable goal.

I never thought about everything the car multimedia system was doing except playing music and it’s true that it might be difficult to swap them now that everything is managed through them