Ok so there are a TON of boost guages out there. Any way to tell if any are better than another? Mechanical pickup, vacuum pickup, digital pickup? Analog? Again this is something I am totally unfamiliar with. I plan on getting a 3 guage pod since it appears that the Subaru guages are kinda useless...I want something that is going to tell me exact numbers, not just a general range. Anyone have suggestions as far as important things to monitor in the rex?
Well there are mechanical and electric gauges. Both involve tapping into the BOV hose, one involves running a small vacuum line to the gauge and the other an electric wire. You can get gauges with digital or analog displays. I think stock boost should be 14.5 at WOT and should pull 18mm Hg of vacuum at idle. I've got some cheap Autometers that I got a good price on, they work pretty well, took an afternoon to install.
Digital is a slight bit more accurate. For boost levelsthe STI boosts around 14.8-15 psi and the wrx boosts about 12-13.2 psi. as for gauges I have an autometer phantom works great and takes about an hour to install.
http://www.cars101.com/subaru/impreza/wrxsti2004.html Thats a sight for accurate details of how your car should perform and what type of equipment it has. Save yourself some money and get a mechanical boost gauge there isn't much difference. You should probably tap your boost gauge into the same line where your stock ECU reads boost, which is the intake manifold. On the front of your intake manifold there is a barb that bends 90 degrees down. You make a t-fitting into the line there. There was a boost gauge thread going around recently that has the picture attached of where to tap into. There is a set of Defi's that match the colors of your interior lights, but they are kind of expensive. If you don't care how the how thing looks lit up, then get whatever gauge you want. http://www.wrxatlanta.com/forums/showthread.php?t=8201&page=2