first off what car are you converting to manual? reason I ask is because you say you have a cable clutch whereas WRX's have a hydraulic clutch. I guess you could probably put a cable clutch... anyone see a problem?
you will need
flywheel-clutch disk-pressure plate
manual driveshaft(easier to just use the whole thing)
cruise computer+cruise clutch relay
starter interlock relay
this should spell it out pretty well