This is a really good reverse engineering exercise but as a cautionary note:
If you are doing this in your real car most of the trim on the dashboard is secured by plastic clips. You need specialized car trim tools (similar to the phone case ones but well bigger) to remove them along the edges without denting the outer plastic edges.
Also most of them are meant to clip-on once. So if you take them apart too many times you might start seeing gaps on the trim and things not properly fitting.
Again it might not be something you care about but just thought I would mention. Ideally you would be better off getting one of these from after-sales or 2nd hand from scrap parts and working on a bench top with a 12V line.
They also explore using a serial connection at the bottom of the chassis. It is specifically that part of accessing the bottom of the chassis that I was advising some caution.