Just had my first ride after installing the Progressive 440 rears and what a night and day difference!
Each bump was literally bone jarring on the stock suspension and it was so stiff I had to fight the bike to stay leaning in corners. Now, especially when cornering, it's like I'm gliding. I can lean more, response is far more fluid and quick - absolutely unbelievable upgrade!
Going to have the fronts done (Progressive again) in a couple of weeks as well and will see if that makes any further difference.
In summary - all I can say is WOW.