Comes factory on GT500 im not worried
i dont think its a good idea to "restrict" the crank pressure specially in boosted applications, this pressure needs to be vented or released from your engine or you might push a seal out causing an oil leak,oil separators might help a bit but nothing beats an oil catch can set up.
you are right on the money... pressure in the crankcase WILL affect HP this is why you NEED to vent these gasses out... thats why when he stated "restrict" I said "WHAT???" thats exactly what you don't want to do.
your pcv valve on your drivers side of the engine is connected to a vacuum source in this case your intake, the passenger side is connected to the intake tube where fresh metered air enters to replace the air that has been pulled out thru the drivers side, i say metered cuz it went thru your mass air, if you restrict the pcv valve and have excess crankcase gases they will find their way out thru the passenger side and entering your engine thru the throttle body, as you can see its a no win situation, as i stated before an oil separator will help but the one that will completely eliminate the oil mist entering your engine is a true catch can set up , unfortunately installing breathers on will only leave a mess of oil cuz they will get saturated with oil and start leaking all over your valve cover.