This Jubu Racing output shaft and differential gear changes the final drive ratio of your 6-speed, C60, C64, C66 Toyota or Lotus manual transmission from a 4.529:1 ratio to a 5.0:1 ratio. The change greatly improves acceleration throughout the closely spaced gears. This kit is tailored to NA vehicles on tight road course use, but its superior strength also makes it a good choice for those having final drive gear breakage issues.