Yosh RS3 4-2-1 Full System. fstbusa-TRE is a timing retard eliminator. It gives the Busa much better throttle response in 1-4 gears. An added plus is that it (Ivan's TRE) tricks the Busa into thinking it is always in 5th gear. Why is this important you ask? Because as you know, the Hayabusa is factory governed not to exceed 186MPH if it is to be sold in America. Unlike the Kawasakis which are governed using the speedometer, Suzuki uses the combination of gearing and the tachometer. When in 6th Gear, if the bike reaches the necessary RPM to propel a stock bike past 186MPH, it automatically lowers the rpm. Ivan's TRE tricks the bike into thinking it is in 5th gear even when it is in 6th, effectively bypassing the governor. great performance mod for 30 bucks!! I read this stuff on the motorcyclistonline website.