Your stock bov is recirculating, so why replace it if it works fine? An aftermarket bov will a) get you defected, b) cause stalling issues and popping as it vents metered air c) cost lots of money d) make everyone think you are a dickhead.
So you are basically paying money to sound like a dickhead, get defected and make you car run worse. Seems like value for money I guess?
Holds over a bar no problem.
Plenty, get a GTR bov if you have issues, they will run 30psi fine.
edit: on 18psi with a stock rb25 bov I get a tiny bit off flutter when I back off on a WOT gear change, but it flows plenty for the rest of the time.