A couple of things-
You can build your own system with all new parts for about $120.00. Non-turbo'd idi's stand to to gain just as much, if not more benefit from a water/alcohol mist system as turbo'd engines, especially from the standpoint of keeping EGT's in the sane range. As WMO Guy already mentioned, they are great if you're running home brew- steam cleaning injector tips and glow plugs can not be over-appreciated. From a power-adder standpoint, yes, you will see a bigger gain if you're running a turbo, but there is a small mileage and power gain even without a turbo. Yes, your dynamic compression is raised when water flashes to steam, but it is within the stock-build abilities of your engine to handle it. As for the alcohol burning- I have done some research on this recently and the general consensus is that you add alcohol to the water to make the water evaporate and cool faster, not as a fuel additive. THAT BEING SAID- [B
]there is a fuel out there in the land known as ED95 and it is 95% alcohol and 5% gasoline.[/B] ED stands for ethanol-diesel. Personaly I never go over 25-30% alcohol in my spray rig and have had zero problems, however I do not doubt that when you start approaching the upper end of the mix ratio, bad juju can be expected.
As the Buddha says- "Moderation in all things..."