Changing out the dash and door trim was a piece of cake on the MkVs. I swapped out the engine turned trim on my 08 R32 for pieces that were painted Tornado Red, to match the exterior.
The dash is ok in the Mk VI, but the doors require that the card be removed as the trim pieces are "melted" in place from the back side. It's anyone's guess how hard it will be on the VIIs, but one thing is for sure: there is quite a bit of it.
Reminder: GTI *CONCEPT* - that can be easily changed in the final production. Yes, if it goes that way that'd be bad. But unlike some of the other things (adding a mechanical handbrake & redesigning the center console to accomdate it, for example), it's trivial for them to change trim pieces between the concept car and the final production version.