There must be something I can do .
Traditional engine tuning (free flow of air and fluids, much labour but no parts/money needed), if you want to stay with 125cc.
With plug & play tuning you can choose big bore kits (not very economical) and/or transmission tuning (same engine power, but better usability at most speeds).
I've seen a full race exhaust system for my bike would that not change anything ?
Your money pocket becomes lighter.
Imho: Don't mess with a perfectly running scoot unless you think you are a better engineer than the manufacturers.
Buy the Kymco MyRoad 700i or any other faster bike.