i think it should be said that this is only used when the car is at WOT only

In MY case, yes. In all cases, no. Delivery can be proportional to engine rpm'* or duty cycle of the FI'*.

Water/Methanol must be injected at above 50psi to properly atomize. Lower than 50psi causes greatly reduced air charge cooling as the result of larger droplets and their reduced total surface area.
Methanol is a high octane fuel that is extremely resistant to detonation with an excellent cost/benefit ratio. ($1.50 - $2.00 per gallon.) Its high latent heat of vaporization also makes it an excellent air charge cooler which means a denser mixture and more horsepower. Because of these facts, it is a better anti-detonant than ethanol or iso-propanol although they will work in a pinch. It has however only about 60% of the energy content of gasoline by volume so about twice as much is used to make similar power if used as a straight fuel.

Centrifugal superchargers/large turbos: Generally, at 50% of peak boost the recommended quantity should be introduced. Positive displacement superchargers/ fast spooling turbos: injection should occur at or near peak boost to avoid combustion quench since peak boost occurs so fast.

would it help a N/A motor?

Sure. Slightly. Not nearly as much as a Forced Induction application, but it depends on what you're after.

Probably 95% of all systems are on SC or Turbo cars.

sorry for bringing a thread back from the dead but I was curious, and never got a clear answer.

For the cleaning aspects, water (steam) will work well. For knock or detonation reduction, straight alcohol will help the most. Straight alcohol in significant quantities will slow combustion and likely reduce performance if knock isn't a problem. I inject straight methanol at 60psi set to engage @ 5 psi boost to reduce knock, and it does work, but eliminating it through mechanical or chip improvement is my ultimate goal. Standard fuel injectors likely won't like straight alcohol or water for any length of time.