We contacted a few people with in Mugen about the RR,
They said that there where no plans at all to produce parts from the RR Concept, And that the RR was just a show car/concept car.
The center console is from a Legend (RL) the dash board is from a Legend (RL) or a new Accord (TSX)
I'm sure that they are all non functional on the show car plus the Legend console has more buttons and functions than a NSX has so there is no point in having them.
It's mostly for show.
The dashboard is probably not functional as well since (if it is a Legend or Accord cluster) isn't compatible with a NSX.
A S2000 steering wheel would look better than the Civic wheel in a NSX but thats personal taste both would work.
The transmission could be a race transmission (Hewland, ZF, etc) a Porsche trans axle would work as well.