So now you have gone out and logged your car, what do all those numbers mean? Well the most important numbers upfront are gonna come from the IAM plus the knock and A/F corrections. For the 16 bit ECU's (02-05 WRX's) the IAM should always be at it's max value of 16. For the 32 bit ECU's (04+ STI/ 05+ Legacy GT/ 06+ WRX) the IAM's max value is 1. If those numbers are anything smaller the ECU is not happy and a knock event has happened. For Feedback and Fine Learning Knock Correction there should be no negative numbers. For the fuel trims you want to see numbers between 5% and -5% with zero being optimal. Between 10% and -10 isn't to bad but anything past that I would start to worry about. Negative numbers mean fuel is being subtracted and positive numbers mean fuel is being added.
Engine Load and Engine RPM are the "X" and "Y" axis of the timing and fueling maps (along with alot of other maps). They are important to help pinpoint where and when a problem is or isn't. To give you an idea of what the maps look like:
Injector duty cycle is important to give you an indea of how much injector headroom you have. Generally anything over 90% means it's time for bigger injectors and probably a fuel pump upgrade. Injector duty cycle is expressed as a percentage for easy interpretation but is not a true representation of a percent. It's not uncommon to see a duty cycle over 100% due to how it's calculated by the ECU.
Wastegate duty cycle represent the duty cycle of the boost control solenoid. It along with manifold relative pressure direct (this is your "boost gauge" basically) and target boost will give you plenty of information on whether or you your boost is on target unless your running an MBC. If you overboosting or underboosting these are the general parameters that let you know. IAT (Intake Air Temperature) also comes into play here as the stock ECU has wastegate duty compensation per IAT. Mass Air Flow can be used as a good rough indacator of how much WHP your making. Rough rule of thumb is 1 g/s = 1 whp. So hopefulley this is "How To" was somewhat useful and helped answer some questions. The links below can provide you with more detailed and insightful information.
RomRaider • View topic - Subaru's knock control strategy explained
RomRaider • View topic - Turbo dynamics and boost control explained
RomRaider • View topic - How To: Make useful data logs
RomRaider • View topic - Injector Duty Cycle
RomRaider • View topic - How To: Understand And Use Learning View's Knock Information