Did you get a narrowband A/F gauge or wideband? Your WRX has a wideband o2 sensor, and if you bought an Autometer A/F gauge, sell it. The Autometers are narrowband, and won't work on your car. As far as the oil pressure gauge, you'll have to tap off of an oil line somewhere and install a T-fitting to go to the gauge or the sending unit (depending on what type of gauge you bought). It's pretty easy though. Other than that, if your gauges have backlights, you'll have to hook up power and ground under the dash somewhere..