I thought this episode of Horsepower TV was very well done and did a great job of visually explaining how a water/methanol system works and some real world NA and
supercharged before and after results. I would've loved to see it installed on a turbo car, as that is typically the best case for maximizing power potential on pump gas.
Here's one of my videos, in this episode of "Tom's Turbo Garage" I get my Methanol Injected Eagle Talon back up and running. If you just want to see the water/methanol stuff, fast forward to 7:58.
Another great video that does a wonderful job of visually explaining the benefits of water/methanol injection.