If I may, I would like to piggy back your question with my own question on CAI and I am new to this stuff too.

I have read various posts that state that fuel economy increases after installing a CAI (I am considering the AIRAID). Not being a mechanic, why does this set up increase the fuel economy? I saw someone say that it increased fuel economy by more than 3 mpg, is that a fairly safe number to use in considering such an upgrade?