Can you share the link please, I don't see it on the Ohlins site.Ohlins have a rear shock for the 821 on their website, ohlins.com .
I think I might pick one up for next season ( around March).
Yes that's the one.Are you referring to the DU 506?
I ride my bike pretty hard, tight corners, late breaking etc and I can't justify replacing the rear shock as the stock handles my street riding needs pretty good. The forks is a different story but you have to remember that you will never get your money back for the forks if you sell the bike.
If I were you and I am not happy with the 821 I would switch bikes before making expensive modifications.