At around 800HP, your stock throttle bodies become a restriction to the intake system. By enlarging the diameter of the throttle bodies from the stock 60mm (ID) to a massive 73.5mm (ID), we increased the cross sectional area by 50%. This provides much improved power gains ? especially over the 1000HP mark. The highest horsepower producing R35 GTR Throttle Bodies now come in two configurations:Vibrant HD or Standard. We also include extensive installation instructions that make for an easy install.