FWIW....During the Gilardoni drought about a decade ago, Mark Etheridge at MG Classics offered exchange/reclaimed nikasil plated cylinders by Millinium with CP Carillo forged pistons, new wrist pins and he gapped the new rings to the cylinders (base & heads gaskets included). The price was competitive with what Gilardoni's had been going for. And, the cylinders had been opened up to near 900cc's total displacement, iirc. Mark suggested I rejet the carbs to 50/150 from 45/145 (again, iirc). No special machining was required to the block or crank although I did have the crank out to clean sludge trap and have recommended Guzziology mods performed to it (polish, radius journal, chamfer oil holes, etc.). As for the slightly larger displacement relative to increased hp/torque, I have no idea if it has more get up & go than it did before but it runs great. I've got about 11k miles on Mark's kit now with zero issues. I have to say that the CP Carillo forged pistons are/were beautiful, they looked too nice to be hidden inside an engine. Good luck!
Art