Hi rx7
Myself, I would not remove the PCV valve from the system unless you decided to turn your ST into a dedicated Track car where your basically driving flat out or parked. Lots of throttle and lots of boost is going to produce more blow by.
As you would know, when the PCV valve opens crankcase fumes are draw into the inlet manifold, also fresh filtered air flows into the crankcase through the other hose connected between the valve cover and the inlet tube. This flow of fresh air helps to purge moisture and other crap from the crankcase as the engine comes up to operating temp from a cold start.
Removal of the pcv valve and going to open vented system can cause sludging of the oil because the condensation does not burn off properly.
I would just go with a catch can in the OEM system.