Who's experimented with this kind of stuff on their Grand Prix, N-A, Turbo, or superchrged...

I'm looking into top-swapping my car sometime in the future, and I've came across Snow Performance "The Water Methanol Injection Experts". I'm not trying to make "like a thousan horsepower" i'm looking at reaching the 300-350whp supercharged, which i see as being reasonable for supercharged (I know i'll be expecting to spend some $$$) and i was loooking into these types of injection systems.... Has anybody used one, and how well (if well at all) does it work or you??