Grab a TST variator kit, to give you a more acceleration, and pull all around. Also comes with alum drive face. The TST variator is a dual ramp design, to help with bottom end as well as top speed. Stock Zuma 125 are happy with around 11g rollers.
Get some here: https://www.scooterswapshop.com/products/zuma-125-prima-rollers