| As far as I'm aware the later type ducati cylinders are no larger a piston as the early ones. They have an improved seal design that stops them leaking. They will probably feel better due to you rebleeding the whole system after fitting one but technically if the piston is no bigger, it won't be any lighter. I've replaced a few of these on 749/999 S4R etc. with my own cylinders and the STM ones and then they've been light.
There are 3 stock cylinder designs out there. The early ones are plain faced, the second ones had the Ducati "roundel" cast in the face and the latest are the ones in Keefy's link with the 12 point "torx" type cap front.
I believe the changes were around improved seals etc. to stop the leaking the earlier ones suffered as soon as they saw fresh air.............
I have more STM units in stock as well as my own. Both are £100. The latest STM are a little more than Dibbles "steal" but still a lot less than their £165 rrp...................... | 
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