there is a lot of info on the web on WI - the pro's and cons. It's used a lot in the US on big boost (3-4bar) cars as it's the only way to stop det - it still reduces power output in most cases unless you map the car with more aggressive ignition and/or more lean, which is not that much different to running a proper map on a 1-1.5 bar engine with decent cooling in the first place.
The biggest cons for me are:
1. Injecting water dampens the spark, and can rob power.
2. if you need more cooling the get a better intercooler.
3. if you map the car for water / methanol mix - or with just water, then if a jet or something else fails then your map will be way off...guess what comes next....
4. You make things more complicated - simple is best as less to go wrong IMO...
You can have a system that senses failure and flicks over to a different map - a unichip could do this, but I am not sure if this can be done with a flea map.
There are plenty of people out there that are big fans of WI - but I'm not one of them.
