[Corey]

Originally Posted by HID

I am from the Audi crowd and when people put BOV on Audis, VW, Volvo, Saab, Porsche, Subaru, and countless other cars with complex ECUs, they usually run rich for the moment that the ECU does not sense the recirculating air.

When you want the sound, you just buy a good free flowing intake.

If for some reason the stock diverter valves cant hold the amount of boost requested, you upgrade to stronger diverter valves.

I will post a video of a properly functioning DV valve.

It isn't that the ECU is "complex" or isn't, it's just that it's tuned for the valve in it's stock form (usually recirculated) and if that is changed without compensating in the ECU's tuning then it will lead to what you described IF the car is equipped with a MAF sensor. If you want to vent atmospherically on such a car you'd need a piggyback controller/standalone/rom tune or to completely replace the MAF with a MAP system which usually requires a stand alone anyway.
Switching to an atmospheric valve in this application will provide no benefit other than a louder sound. Turbo lag is in no way affected. The blow off valve opens when it sees vacuum in the intake manifold, i.e. when you let off the throttle so the turbo isn't spooling at that time anyway. It prevents surge on the compressor side but has zero affect on the exhaust turbine which would spools the turbo. Maybe that will clear some things up.