FAQ: These are not DIY manuals. This is known throughout most of the world as "educational material"
ECU Tune: Flash tuning of the OEM Siemens ECU, user-tunable piggybacks, and standalone ECU replacements
Intake: Air intake, throttle, intake manifold
Turbo: You can read, right?
Ignition: Sparkplugs, basically
Exhaust: Everything after the turbocharger, pretty much
Internals: Building your motor; anything and everything that does not simply bolt to the car
Cooling: The things that keep your motor from becoming a large aluminum paperweight
Mounts: Engine mounts and stabilizers that keep your motor from smacking a strut tower when intoxicated
Meth & NO2: Water/methanol and nitrous oxide use & application