Circuit Werks latest 2003-2005 Infiniti G35 Resonated Test Pipes. These are the newly designed Resonated test pipes, this will help with the sound of your VQ motor, smooth out the exhaust flow along with reducing exhaust drone, and not to mention the additional performance gain versus any typical test pipes. Fits both Auto and Manual transmission. (Provided O2 Extensions may not work with automatic transmission models) These test pipes feature a 2.5" outer diameter with a 2.25" inner diameter design, Built in flex pipes to absorb all the movements from your motor and is a Direct bolt on with o2 sensor extenders. Sorry, no instructions and please note that this replaces your factory catalytic converter and might not pass emissions in some States. Off road use only. Other models are also available.