Re: cbr 918 97 tail swap 05 600rr
Welcome to CF!
I haven't done it myself yet but being a fabricator of sorts and watching on here it seems people all have their own ways of going about a tail swap.
Unlikely that you will find a suitable doner tail that will just bolt up so grab some calipers or cardboard (your choice) and a hacksaw and start building your own.
Looks like tank to seat fit, taillight, and where to put your battery and wiring are more of a PIA than just getting the rails where you want em.
"Practice till the hot brass burns the cheeks of your ass" F. Bob Chow