So to add some details to this thread

What were some of the changes needed to swap instrument cluster and steering wheel?

Did you relocate the battery to the rear? How did you run the cables?

Rear subframe? Did you swap the RS6 subframe with diff?

What about fuel tank and pumps?

What about the coolant after run pump and wires. Did you have to run new wires?

I have feelers out for a S6 and could be doing this soon. Must need head examined.