Ok, I guess on a race motor it makes a little bit of sense. I based my statement on the pictures I have seen of turbos after sucking up rainwater due to poorly located cold air intakes. I believe I would spring for some more/better injectors to improve atomization rather than spray it through the turbo even if it was a racecar.
Besides, what about the heat transfer? It's always more effiecent the wider the tempature gap, and, up to the point that it vaporizes, the water is still fine for phase change heat transfer in the cylinder. Or have I misunderstood something? I've never actually used water injection, though I did consider it for a while in my 2.3L ford turbo.