I am assuming it has to do with the exhaust, and not having it properly dynoed, however I notice that my old mans 2000 Hayabusa has much better acceleration than my 2001. I have a Boz Bro B2 Moira 4-1 full exhaust. My dad has dual Yoshimura RS-3 slipons mounted on his. Neither bike has a power commander. Soon as you inch the throttle on my dads bike you can instantly feel the torque take off. As for my bike the throttle does not roll on with nearly as much power; you have to apply more twist before the power comes to the bike. The speed limiter has been taken off my bike, but we are talking about 0-100 here. I was just wondering if the 1999 - 2000 models were just faster before the ban on the speed was implemented, however from what I've read the engine remains untouched. Anyone have any ideas if there was any specific model difference that would cause this?