I've found that I have a problem seeing the speedometer in unfavorable light. If I am driving in the sun or bright conditions, often the speedometer is in relative darkness and I cannot tell how fast I'm going.
I tried a number of solutions, but found a small LED directional flashlight, and attached it with some Velcro to the underside of the plastic shield over the speedometer and tach. This stays put, activates easily, and gives me the light I need to see the dash when I'm driving into the sun. Not a life changing mod, but a good $2 fix for an annoying issue!