the PFC stands for "power fc" it is a new ecu for your car that is made by apexi (if you dont know what a ecu is, it is the computer that runs your car) but the good thing about this ecu is that you can adjust excatly how your car runs ie. port timing, fuel maps,ignition timing and every other aspect of the engine. it cost about $1000 for the power fc, $400 for the commader and like $400 for the datalogit. The commader is a basic controler for the power fc but cannot control all ascepcts of the ecu, while if you get the datalogit you can connect your laptop to it and update everything from there. You dont want to buy this unless you know EXACTLY what you are doing, they are not smog legal ( not obd-II), but if your a hardcore racer with the cash it supposedly can add 10-20 whp with it being dynoded correcly.