The RB N54 PCV Valve is an upgraded replacement PCV valve for your N54 Engine and is strongly recommended for your high performance (or higher mileage) N54.
The OEM plastic PCV valve does not hold pressure well even when brand new. What the leaky PCV valve means is that when you are in boosted conditions, the "highly" pressurized PCV valve leaks turbocharged pressures into the crankcase. Pending on the condition of your PCV valve it could leak worse than others. Also if for some reason your valve cover is cracked, loose, or has a bad gasket; you also could develop a pressure leak either external to the engine or internal into the crankcase causing further pressurization of the crankcase or other oil loss issues.