I also have a diablo tuner i can sell you with it to calibrate the gears and what not. I was selling it for $200 so tuner and diabloe $400 together!!!! you will see the most bang for your buck with these 2 mods. I went from a 14.4 to a 13.9 with these gears alone cuz i had the tune already. I have an auto :( but ya.