some of the aftermarket ones don't have the port to connect that breather hose to. if u look at the base of NISSAN's intake, u'll see a hose running from his intake to his head. if the intake u buy doesnt have anywhere to hook that hose up to, be sure to grab a mini-filter from discount, otherwise u will eventually start blowing seals. or if u live in spring hill, u can pick up a free one from Outkasted24.