In order to achieve 100 mph using an MF480, you will need a small, very clean air frame with lots of power. I don't know how your eyesight is but I would have a tough time keeping a small plane in sight at that speed. At 100 mph, the plane will be moving at 147 ft/sec, covering the length of a foot ball field in two seconds. Not a whole lot of time to take any corrective actions.

To build a plane that will fly at 50 mph is easy to do. To make that same plane fly at 100 mph, you need just about eight (8) times the power.

Sounds like an interesting project.