The Serrated/Helix combination design creates intake turbulence in the combustion chamber. This turbulence breaks up the fuel which creates a more complete combustion cycle increasing horsepower, torque and improving throttle response. The Serrated/Helix combination design also reduces intake whistle that occurs with Helix only designs. All Silver Bullet Throttle Body Spacers are constructed from 6061-T6 billet aluminum precision machined for light weight, high strength and perfect fit and finish. This Silver Bullet throttle body spacer uses all factory mounting locations providing stability and a hassle-free installation. Silver Bullet Throttle Body Spacer Kit Lexus IS350 21-24 V6-3.5L Lexus IS350 21-24 V6-3.5L