Follow the directions (in Japanese) for a relatively painless install. You basically strap these grips over the metal of the existing pedals (take off the rubber grips that are on there now).

The only problem I ran into is that the strap that holds the gas pedal on doesn't quite wrap all the way around the back of the pedal. I bought a copper pipe strap that would be long enough, bent it as needed, drilled holes and screwed away. Nice and tight.

If you'd prefer something that fits a little better or a little tighter, check out pedals that actually drill INTO your existing pedals.