Hey David,
To be honest, I really can't notice a difference. Maybe a fulltime biker, racer etc could, but not I. Now the difference just looking at the springs is huge for they are true progressives (you can really see it comparing the front), so you know (hope) they are doing the proper job. I admit that I went with the rears for the blacked out look. Now, a friend of mine who rides a ZZR says he is blown away by the handling and braking of my bike, and he has ridden it "before" and "after". Sorry can't be too much help there.