[davidgrey50]

I've been riding a PCX125 since April. Herewith my .02 FWIW. At (indicated) 80 Kmh the PCX is surprisingly smooth, stable, and composed. At 90 Kmh it's getting buzzy. At 100 it's bouncy, buzzy and you just wouldn't want to be on one that goes any faster. The short wheelbase and small diameter wheels are inherent limitations. Additionally, the effects of large trucks passing and side winds are pretty major. It's amazingly good for what it is, but I think you may find it would not be the best base for your proposed mods. Some of the Taiwanese scooters have appreciably longer wheelbases and larger wheels.