I had a ducati corse slipper with carbon clutch plates fitted on my just sold 999s.
The bike was fantastic coming into corners as i could change down the box without any fear of the back end locking up and gave a lot of confidence.
The only down point was a grinding noise when moving off quickly or when say on a hill and slipping the clutch as you move off,but most people i have asked seem to have experienced this themselves.
As for the lever clicking ,i found that blipping the throttle as i changed down the box seemed to eliminate this.
Overall i think they are a great piece of kit but i do not know where they get the prices from.
Good Luck