I'm a little behind on the thread, reading up on it right now,
Just 2 questions,

1- By how much is the speedo off? (indicated MPH vs GPS verified MPH)?

and

2- Since the engine has a big bore, I can imagine the engine vibrations are caused by an incorrectly balanced counter weight, as the newer piston is both larger and heavier than the stock 125cc piston.
So my question is, has there been any remedy, or easy fix to counter the vibrations, or is the only way to re-balance the counterbalance?