The section that states the tail section from a 03-04 zx6r fits needs to be revised. The undertail doesn't fit without considerable modification.The main portion will fit (the tail) but if you try and use the undertail portion you will find the following issues:
1. There is no hole or mounting holes for the rear lock cylinder. You can make this work by drilling a hole and using a standard nut and bolt, not quite as clean as factory but depending what hardware you chose most people will never notice.
2. Look at the lower portion of the under tail from the zx6r, there is a large hump for the rear tire. This will keep you from having it sit flush and lining up with the tail section. You can make this piece work and basically look just like the original by taking a dremel and cut off wheel and trimming around the tire bulge. Once this part is removed the undertail will line up as it should.
Anyways, just something to clarify the blanket statement that the tail section from the zx6r fits, it's more of a "it fits, but...."