Had my old Katana set up by an engine tuner with nothing more than a fuel air meter. I complained re throttle response and he told me to roll the gas on not wack it wide open, worked a treat, soon got used to it, I think most expect to be able to abuse the throttle as they did with the airbox in place and of course it hesitates so they think they have a problem. I must have done 20k with filters and was no different to stock once you got the feel for it