Zongshen predator 125

iv Scrappe dthe idea of importing a Galaxy XTR 250 now that no one wants to come close to importing a chinese motorcycle around my area :confused1: so tempted by the Zongshen predator 125 but im wondering how can i get more BHP as its only 11bhp and 60mph max and for me its 65-70mph minimum, would changing the carb for a better genuine manufacturer one be good for abit more oomph im also considering changing the gearing for better top speed but would need advice to sprocket sizes aswell