GY6 - yes, from what I can tell my bikes used many standard GY6 parts for rims, brakes, switches, etc. But except for replacing brake pads, throttles, and tires, I haven't used any other replacement parts in five to six years so I'm not 100% sure what is truly GY6.
I bought the ZEVs because I do my own maintenance and wanted easily available and inexpensive parts and I was able to get a great deal on tax credits in my state at the time. For people looking for local support, maintenance service, or higher performance, I would buy a Zero. But for me it's worked out well.
ZEV T7100, 84V, 60AH, 65+mph; Mods: TNC throttle, windshield, Cycle Analyst , Cell Log , and custom charger
Kymco GT300i - for long rides through the Rocky Mountains
Big EV Grin.