http://www.snowperformance.net/ has the details. What are driving that has those mods with only 9psi of boost?
Basically it is an injection into the air intake at a recommended mix of 50% water and 50% methanol. Both components cool the aircharge and combustion chamber. The methanol is also a high octane fuel that increase the burn. It makes the EGT's lower and gives you 50-100HP. This kit is also a prevention for detonation they say.