For anyone out there with a Subaru they want to make a little faster and learn a lot about,
go here.Romraider is an open source tuning solution for Subaru engine management. You can change nearly anything in the stock ECU. You can totally blow up your motor if you want! Your investment is a $70 cable from a company called
Tactrix. Additionally, you can log data from your ECU to understand what it is doing. In the case of my 02 WRX, I can see when the turbo is making what pressure, what ignition timing looks like and what duty cycle the fuel injectors are running at. See pics of maps below:

Then, when you really want to have fun and risk spending serious coin, try some little changes...baby steps. So over the last year or so, I've gone from a motor pulling in 137g/sec of air at 5k rpm to a motor that pulls about 160g/sec...about a 17% increase in horsepower. Having my oil analysed has shown no adverse wear on the car...just tons of fun.