I put a Works Performance on my old 1986 BMW R65 and it was absolutely FANTASTIC!!! They have a lever on them that you flip to instantly make it set for 2 up or loaded riding, and then flip it back for just regular single riding..
I wish I had spent the extra money to get a Works shock, rather than the Progressive I currently have. Much better piece of equipment.
I ended up selling the shock with the bike, to a friend and he and his wife both love riding the bike because of the shock. After 4-5 years and around 35-40K, it's just now getting to the point where it's in need of a rebuild..