when you want the blow off type sound, take the tube that recircs the air to the hard pipes above the recirculation valve and disconnect both sides. your car will idle really bad and want to fall on its face but when it releases "blows off" the air the sound is pretty loud maybe louder then my RFLs, and if you wanted, they make caps for the part were u removed the tube so that your car will idle right. and you can always reconnect the tubes and have the quiet recirc balk. -dan