actually, its a whoosh then a whistle at the end. If you are on low boost, than its a whistle. Hight boost, all whoosh. Most of the time its in between. This is with aftermarket intake. Also this is recirculated. I am curious as to how the HKS one is recirculated? I heard a few sound clips on a website (i think it was blowoffvlaves.com ??) but it sounded like a muffeld whoosh, way worse than the higher pitched whoosh of the greddy. Anyone with an HKS recirc with aftermarket intake care to chime in?

 

I don't know where all you guys get this whooosh sound from??? mine holds 20 psi quite fine and it whistles the whole time no matter at high boost or low boost....I've never heard a whooosh sound come from a greddy type-s.....in fact it almost sounds like the eclipse from the fast n the gayness in the first movie....