Hey Slurp.. did you measure the Diameter of the Injen and the AEM??? Were they same?? If not I wonder why. I remember reading that these intakes are made not only to force ambient air into the engine but also due to the exact length of the CAI, and I would assume diameter,.. well check out this article that was in NPM... It will explain it better then I can
http://www.nissanperformancemag.com/...fthenerds1.php