Maybe it's because I was reccently bashed apart by a car, but I do not want to see more than 45 mph on a 50cc bike. The Bi-turbo is plenty of "mod" for me.
I'm lucky to be alive at this point. The key to a safe moped (in my opinion) is moderation. Nothing moderate about 150% performance.
I think I'd like to have a ped to soup up for off-road and a tame one for street riding.