A warning to those considering the STi branded pressure plate and flywheel:
Apparently these two parts are designed ONLY to be used with the STi flywheel. We have been battling an issue now with both the early AND late production 2.0 WRX flywheels not working properly with this setup.
The car has gone through 3 setups now:
BPM Flywheel + stock pressure plate stock disc = OK
Stock Early Flywheel + STi pressure plate and disc = Shudder and slip
Stock Late Flywheel + STi pressure plate and disc = Shudder and slip
Stock Late Flywheel + Stock Late Pressure plate and disc = OK
If you are planning on doing the STi pressure plate and disc, I would advise the STi flywheel as well. The distance from the mating surface on the pressure plate to the flywheel differs by 2mm from the STi pressure plate to the stocker.