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Almost all "CAI"'s have accommodations for the PCV vent line ... without one it would just as you mentioned be a"breather" rather than provide positive crank case ventilation. A properly built product should have two ports, one for the IAT sensor and then closer to the throttle body one for the PCV vent line. Installing a separate valve cover breather on a NA motor is going backwards in functionality.
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I’ve been looking at the different CAI descriptions and I can’t find any that say what additional connections are built into them, if any. I would think that would be pertinate info to have before making an informed buying decision.