Not all CAI are created equal, the ones on Ebay are crap, and most of them are not made to the standrads of other brand name Intakes. If they were all the same than why does the AEM CAI make more power than a DC Sports one. It's because the AEM is of course AEM pioneered the Cold Air induction system for sport compact cars. Every system is C.A.R.B. exempt, or pending C.A.R.B. exemption (50-state legal). They utilize a complete hardware kit with soft mounts for a guaranteed perfect fit and have a lifetime warantee. Also, the bends and lenght of the intake make a difference. The ones on Ebay, are usually just machined pieces of pipe, with generic filters. Yes, an AEM comes with a specific filter to oimprove perfromance as well. Like clickwir
said, you get what you pay for, if you want a neato sound, buy a generic one offof ebay, and be sure to pick up a set of Neon windshiled washers as well. But if you want quality, something designed just for your specific application, and something that will earn the respect of fellow sport compact enthusiast than go with AEM.