I'd like to know the difference between the STI BPV and the WRX BPV. I've read that the WRX has a vacuum line attached and the STI does not. Becuase of this the spring in STI valve is "lighter". Any specs would be appreciated.
Is there any difference in the maximum boost that can be held by either valve. Stated above the WRX holds to 20psi. How about the STI valve?