You will need a service manual for your Gsxr, and one for the correct year Busa, which is on the site somewhere
(I will look and link it here if no one else does first).
Then go point to point through the wiring diagrams.
I have seen it done before, but am not sure what pins at the guage cluster or at the ecu that need moved, but there wasn't alot, 4 or 6, sorry, it's been a long time ago now, lol.
welcome to the org