As discussed on the R forum all the mechanics are in production. As it is just an R with a modified engine. An engine which is being used by Audi.
Also, the video says it is to celebrate 40 years of the Golf.
After much deliberation I don't think I would bother upgrading from my R. I could get my R to 400bhp for not too much money and I don't have to have those seats, plus I get to keep my 5 doors!
Still, there are plenty of people showing interest.