should get your ECU reprogrammed and you can get an inline from MPS or Schnitz or Boostbysmith.com
I use the ECU for nitrous on rare occasions so I can't use the shifter function. So I use to run Cycletek Air Shifter which worked awesome but I decided to get rid of it for more street riding and road track excursions. So I went with this quickshifter from this place: Dano's Performance as it has it's own kill box.

I have not put it on yet but will let you know how it works once I get it on.
if you have/use the ECU Editor, then you dont need anybody's kill box. the Hayabusa has one built in! if your already flashed for an airshifter, you can use the same setup.

ECU Flashing
I use an MPS quickshifter it would work great for your bike. you can click the link in my signature to find out all the details. But i did a complete write-up on the install for my cbr...if your interested in the write up just PM me. Good luck with the search, there are plenty of awesome choices out there :thumbsup: