03-04 are the best years, thats when they went to 636 cc’s ~135 hp~, the newer ones are nice as well, but i hear there are problems seeing the guages unless laying flat (not most of the riding)
I’ve got an '04 but it needs painted and has plastics damage around the turn signals from being dropped (not while moving)
I realize this is not what ur looking for but my opinion holds true of the years for zx6rs. Def do not get a carbed bike 01 + 02 may be carbed, not sure.
01-02 ZX6R’s were carb’d. I sold my 02 6R a few months ago, nothing wrong with carb’d bikes, it ran well. 03 and up they changed the body style, went to FI and up’d the hp. The 03+ models are the better bikes.