Mallosi, polini, stage6,...
A lot of people here will tell you it's a bad idea. That it won't work or will ruin your scooter.
Forget it. If you want to do then do it. Use quality parts and realize 1, you won't see mammoth gains and 2, you have now made another part of the scoot the weak link.
Best mode of increasing performance is upgrade transmission... Variator, weights, clutch, clutch and torque springs... Belt even... Then open air filter, exhaust and carb jet. Then big bore kit, bigger carb...
Lots of steps that yeah, will cost more and require more set up and possibly more headaches than buying a bigger scoot.
But then you'd have a stock big scooter and not a bad ass tricked out little scooter!