I think we are getting to a point with imports that for rare examples such as this, perusing the auction dross is probably not the best source of cars. There is a retail market in Japan as well as auction market, and the Roadsters in the retail sector just seem much nicer than what I see going through the auctions.
While non-residents can’t buy a used car in Japan, agents are not confined to the auction market. Back in the day, in the early days of JDM imports, there was an outfit called Japatrans, who scoured the forecourts for some really special cars. I have an idea that the London-based company, Bauhaus, who started bringing in virtually new automatic Eunos Roadsters (mostly V-Specials) around about 1991, were also sourcing directly from Japanese dealerships.
For these special cars, going to a dealership, or Roadster specialist, is probably the best place. Some examples include Garage Hundred One and D-Technique always seemed to have some M2s on their books. Car Make Corns also sell some gorgeous Roadsters from time to time (not great at the moment though), though rarely have I see a M2-Inc car through them.
This is a strange (controversial) one, NC with a lifter kit.