any MAF (mass air flow metered) car will have to run a recirculating valve.

that srt4 guy is partially correct, because the factory bypass valves in most cases are more than sufficient in doing their jobs....at stock boost levels. like it was said before you may lose power with a VTA (vent to atmosphere - much louder) BOV since the ECU has to find/accomodate for the vented air, which it still thinks that is inside the engine/intake etc. the result usually is idle issues and funky air/fuel ratios during shifting etc.

blah