The standard 100cc cilinders are very slow (relatively), especially in acceleration. Using a different carb won't really help anything if you leave the rest the samen. The best option would be a better cylinder but I'm not sure what will fit on your motor.. but when you do pick one, the rest of the parts can be adjusted to that cylinder. Dont go the other way around, like buying a different exhaust or vario and then adjusting the other parts to that.
Try asking your local scootershop if there is a good one in your area about available cylinders (you'll end up with a fast 70cc I'm guessing)