Fellows, please! It's not about speed ... "it's all about style!" My ped goes under 30 mph, and I don't want to go more than 35 max. Why? The idea of a moped is to move w/in traffic and the environment and have easy access to communicate w/ friends and well-wishers along the way.
Speed is SOOO overrated. I like getting looks and cheers as I cruise around the student ghetto in my college town. It's great! If you go too fast, they don't see you. If you go slow enough, you get noticed and they know who you are. You also get a better view of neighborhoods and scenic vistas.
Instead of speed ... make sure your moped looks sweet. Nice paint, shiny chrome, good working order. Make a scene! Get noticed! Ride at a moderate speed.
Swarm and Destroy!