Since you are running Livernois tunes, you may want to contact them. My W/M system came via Torrie @ Unleashed Tuning & Fast Parts Network, as did my 3 Bar MAPv sensor.
The purpose of the Water/Methanol system is to cool your air charge, which allows your engine to make more power, when tuned for the cooler charge. The 3 Bar MAPv sensor which installs on top of your intake manifold, in place of the 2 Bar one, allows for boost levels that are higher than 1 atmosphere or 15.7 lbs of boost. In effect, Ford's 3 Bar MAPv sensor allows boost levels up to 2 atmospheres. But since our turbos can't build that much boost as they are small, it helps optimize the effective boost.
Note, this does require logging your WOT runs to make sure the new tunes keep your various parameters, such as Lambda (A/F), FRP (fuel rail pressure) and other things, to remain within safe limits.
Darreli is using both on his SHO. His W/M system allows for 100% Methanol.
There are several good articles on W/M systems. Read as many as you can. I found one that pertained to motorcycles that had a lengthy history of their use, going back to WW II airplanes.