From survey, about a mp3 year 2014 500cc piston/cylinder/sleeve Ďassemblyí may be perfect solution: instead of a messy (human variance) unreliable bore-kit. Thatís the way BMWís Italian (Aprilia) 97 F650 sold pistons and cylinders: only in a combined assembly (now I understand why. - Initially, being broke, I assumed it was for grater profit margins alone.)
If I had a link to nested bomís from Piaggio (Question #2), I could verify any other part variances between the MP3 400 and 500 Models (??) for my grand scheme to gain a reliable 6 hp to (Safely) move my 300 lbs away from in front of cars.
Am I the first Thrifty (or Cheap) owner to wonder about this? Any way, Safety First(!) because I am sure I cannot squat 600 lbs :-O