Yes, Josh, I know your car... Just saying that some people use WI with small IC's to compensate for what happens to the charge air after heat soak sets in. People who have a big enough intercooler to prevent heat soak (like yourself) STILL benefit from water injection, and still make big power gains with it. The premise of how it works is similar to an EGR valve. Only instead of adding burnt HOT gasses from your exhaust, you use cold inert gasses that contain no hydrocarbons in order to make the charge air denser (regardless of its temperature). The result, unlike what your EGR does, is that you burn cleaner, cooler, and with more (final) compression.

You have already blocked off your EGR valve, haven't you?

About EGT's...
EGT gauges are WORTHLESS for fuel tuning, and that's a huge, long explanation for those that don't know why and have been doing that. But what an EGT gauge WILL do is give you a heads-up when you're melting your motor. Sometimes they'll tell you a little too late. EGT's are a better indicator of your timing advance than they are of your fuel mixture since it doesn't measure the temperature INSIDE the combustion chamber. I still wouldn't build my tuner car without one because rods, pistons, blocks, head work, etc... is very expensive. It costs a lot less to have an EGT gauge and to just lift your foot off the gas pedal if things get dangerous.

Get an electronic one with a warning light. Computerized gauges with memories are cool and all, but with an EGT, that info will never be useful after-the-fact. Save your money. They're just cool if you like to show off. You'll never learn anything by watching an EGT gauge play back. Non-electronic gauges don't have warning features, but the warning light and/or buzzer output like the Greddy 60mm peak-hold has is worth the $.

I'll elaborate on the fuel tuning vs. EGT usefulness if it's necessary, but I just don't want to see you hose your motor from detonation. You need a parachute if you go skydiving.