It basically is a mixture or atomized water and methanol (usually 50/50) that is injected into the intake which cools the intake charge along with upping your octane level to about 100 (methanol I believe is ~ 116). Your computer should see this drop in temperature and advance timing, giving you more power. The methanol helps control detonation with the increased timing. This is also said to help clean your engine and prevent carbon hotspots from forming. It's worth a shot. Tons of people have been running this for many years. Read up on their site and you'll see for yourself.

- Josh