I find it funny that the makers claim its supposed to give you more low end power and better throttle response by removing the timing restrictions zuki put in the lower gears to keep the bike calmer for the average rider, and also remove the top speed restriction....yet you have folks that swear it makes the bike calmer?, folks that swear it makes the bike stronger (including sportrider magazine, read the link further up)?, and folks that swear it does nothing? Makes you wonder what it really does eh?
I tried one and it did seem to give more low end, but it made the throttle VERY abrupt and jerky on my stock busa...and made it run too rich (it uses 5th gear map for every gear), plus messed with the idle bigtime...but I wasn't running a smart tre either which fixes the idle issues. I took my tre back off and it now sits in a box in the garage
I think except for removing the top speed limiter, most of what the tre does is the same thing as a sugar pill.....its called the placebo effect