here in md we have to tag anything above 50cc but if i had a scoot with a 50cc vin and a 150 motor they can't say sh**
Yep the 50cc is the key thing the police look for - although the law does specify that the scooter has to have a rating of 2.7 hp or less, they'll never be able to prove that! As long as you have the original paperwork that came with the scoot, it would all be good.
The law also does state that you can't operate the scooter at more than 30mph - but doesn't say that the scoot can't be capable of going faster...