If you drive a Honda Zoomer, what is the best performance kit to fit onto it?

Honda zoomer with a speed kit but need a better performance kit as I still cannot over 50 mph and on some roads I drive this is not satisfactory.If you drive a Honda Zoomer, what is the best performance kit to fit onto it?never heard of a zoomer until today but looked it up on wickopedia,,,it lists company's that make hipo parts..funny looking but cool.....i don't know if u can get much more than 50 mph out of it...a smaller sprocket in engine/tranny and larger one at back wheel will help top speed but u lose at low end.