This is just from my experience, there a few here that work and own garages that can correct me or guide you better.
Malossi Purprle Contra Spring
8 Gm Dr Pulley Sliders (I use 7 Gm and like them but 7 Gm could be causing the bike to rev too much and I probably wouldn't know). I do a lot of hills here in Connecticut.
85 main jet - higher is suggested if removing airbox snorkel but Im using the #85 and plan on removing the head soon to inspect the piston once I locate a head gasket to see if Im doing any harm to the piston. Looking in the spark plug hole with a flashlight I see the top of the piston is all black and sooty with a small white spot in the middle. I dont know if Im too rich or too lean. Right now Im having trouble finding a simple head gasket in the USA. Racingplanet has them but last time took over a month to get a simple part.
Id like to upgrade my clutch springs and not sure what to get my self.
Remove the brass cap and get that idle air adjuster screw slotted or use a D-socket so you can fine tune the carb.
Check out this exhaust for performance :
http://www.scrappydogscooters.com/Kymco_Scooter_Parts.html