I dunno if a WAI will get you much, esp. if what I hear about the newer civics having direct injection is true.
If your car has DI, then the motor shouldn't have much restriction/pumping losses generated by the throttle body, so a WAI wouldn't be too useful (in theory)
But then again it's only theory untill someone tests it
And a WAI only involves a few $ worth of aluminum venting, so no big loss if it doesn't work.