I have been running dual breathers for 15 years with no problems. Never had any water in oil or condensation in valve covers when I have adjusted valves. Only time I could see it help if you start and run your car often for short periods of time and don't let it get warmed up.
That is true as short runs without letting the eng warm up is not good. Many run breathers and if you run the eng long enough all the time you may be ok but running a PCV valve setup will help make it better even on short runs and it has not hurt my performance one bit. I like it for the added insurance against moisture buildup in the eng and getting the blowby gasses out of the crankcase faster. Ron
