FWI = Fender well intake/cold air intake, u-bend delete = http://www.pfyc.com/mm5/graphics/new/wb5001.jpg , Donwpipe is the constrictive piping from the headers to the catalytic converter, and the PCM is the Powertrain Control Module(ie. your cars compter/brain). Most people either send in their pcm to be reprogrammed or buy a already reprogrammed pcm.