Here's the deal with the intercoolers :

Basically any intercooler will do for running 7psi. A larger intercooler will just cause a bigger "pressure drop" unless you are running massive amounts of boost. The star kit comes with a very nice intercooler, and should be efficient for at least 350hp..
Now if you want to go with Water-to-Air intercooler: its only a good idea if you run it at the track because the ice water will heat up very fast. One thing you can do tho is run a frount mount and an air-to-water intercooler.

You can actually make your own water-to-air intercooler... Just take a very small intercooler such as the stock eclipse, and built a sheet metal box around it... and will the box with ice water... VIOLA !


good luck