The little NSR50 'Gag' bike with 12" wheels, or the 'full-size' learner-legal version ?
My bike's not restricted, it'll do a genuine 55mph no problem. It's got an aftermarket CDI box under the seat though...
No problem putting one on the road in the UK, but I understand it's all a lot more complicated in the so-called 'united' states.
MC21 isn't exactly a similar bike to the 50. Do you want one of the little ones (NSR/YSR/TZM/TDR/KSR/RB etc.) or a proper 250 ?