As a foreigner I may have missed something, but I thought there were still only 50 states?
Actually I am doing it the other way, putting a cast iron 49cc Minarelli vertical cylinder on my 66cc base.
It is not a simple swap. A new intake and exhaust are needed, a cylinder spacer, a reed valve and some fancy drilling and grinding.
I will have a street legal 49cc 2 stroke 6-8hp engine. Cost will be about $250 plus the $125 Chinese bottom end.
A bit of head and port work on my Grubee 48cc engine had it working as well as the 66cc Grubee.
Ultimately the 66cc will go faster but the 48cc is no slouch. Rips along pretty good at 30mph+ on the stock sprocket.
Steve