As an alternative recirculation valve on the Audi TT RS 5 cylinder engine, this kit is a fully engineered solution offering both significantly improved reliability as well as valve related boost response. Our valve and installation kit replaces the original unit with a pressure/vacuum operated piston valve that still also retains the desirable OEM ECU control over valve actuation. This product has been thoroughly designed and tested with the expressed intent of offering improved valve response and maintaining ECU control while resulting in absolutely NO fault codes, NO check engine lights, and no adverse effects of any kind. All of the necessary components and detailed instructions are included and everything is designed to make installation as simple as possible. This kit is supplied with an additional uprated spring that may be required if the vehicle has had a significant boost increase after an ECU performance upgrade. For those planning to tune their vehicles in excess of 450hp we recommend the use of our FMARSDV ( see related products below )