ERL vs. Spearco
Jackson Racing sells the ERL Aquamist system 1s. And I'd have to agree, $700 is way overpriced. $450 is the price that most US vendors sell the kit for. I purchased my Aquamist system 2c from George's Imports in (or near) Kansas City, it retails for $600. The system 2c is designed to work with 3rd party engine management systems, but you can use the signals from the fuel injectors if you don't have 3rd party engine management.
The pump and nozzles in the ERL systems are far superior to those supplied with the Spearco systems. One nice thing about the Spearco system is that it comes with the tank. If you get the kit for turbo applications, the tank is pressurized by the engine boost. However, the Spearco's pump only delivers about 15-20psi whereas the pump from ERL offers 70 psi on the regular pump (which from what I've gathered is no longer standard equiptment) and 100 psi from the "Race" pump. If you do go with Spearco, be sure to get the pressurized tank. You have to supply your own tank with the ERL systems. I've seen coolant reservoirs for $5-20.
Although water injection is a great alternative to an air/liquid or air/air intercooler. Installing an intercooler would probably be a better option for you. The primary reason I plan on using water injection is because the only intercooler option availible for my other car is $2000. When I add a turbo to the Protege, it will have an intercooler. Probably just air/air.
If you'd like to experiment with an ERL, I have a used system 1 (not 1s) and a new system 2c that I'd be willing to part with for much less than what they retail for. Contact me via PM or e-mail if interested.
I noticed you were using a 10:1 Vortec FMU. Have you been able to get O2 readings from the ECU or find out where your A/F ratio is? The reason I ask is becuase dumping extra fuel is a common practice with forced induction. The extra fuel cools the intake charge just like what a water injuction system would. However, pump gas doesn't cool off the charge as well as a water/alcohol mix. So if you do go with water injection, or any form of intercooling for that matter, you may want to lean out the A/F a little.