ive seen them also jvs . look for a thai wave facebk group.
probably not difficult or expensive to retrofit. drum brakes and cvt's are 100+ year old technology. you can also upgrade front disc . larger diameter, different caliper, more powerful master cylinder. adjustable leverage actuators. why? why bother ? it's easy to forget modern cars stop much faster than these old scooters. need for emergency braking? uh happens about once/ week. golly gee im blathering again