What Kawasaki rear calipers are interchangeable on the 03-04 ninja zx6r 636?

The 03-04 Kawasaki rear single piston brake caliper is weak, and can feel spongey. I was wondering if anyone knows if any years of zx10r or other zx6r rear calipers will bolt up directly. I have tried searching and cannot find much. Thank you very much.