I know im late on this reply, but I have a Neuspeed CAI on my 00 TT 1.8T and it was horrible the first time i put it on. The factory over oils the filter and it causes Oil Blow By. Mass Aif Flow Sesor needed to be replaced. I put it back on about a year later and it works fine, except Cruise Control seems to hate it. I threw a ECP light and the car cuts off every time i use the Cruise Control.... It sounds like you have a Blow Off valve on your car when you let off the gass.... I use it still and like the sound. Good Luck.
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