most aftermarket rotors will be semi or full floating rotors and are made from better material to dissipate heat faster n such. shop around and you'll find that rotors from alth,brembo,ebc,galfer,braking,ferado, etc are all alot similar but then again it boils down to what you've done to the rest of your braking system IMO anyway, you running the stock master cylinder,lines,calipers,pads? i've seen several nice new sets around and will send you some links if you'd like? we run 300mm rotors but if you find a set from several years of the ZX6-Zx6r they are compatible. let me know and i will gladldy pm or email you quite a few links i've saved on the rotors. there are also several other factors which will make one brand of rotor more expensive or "better" than others. i had a set of brembo hp rotors but got rid of them and ended up getting a set of the alth rotors BUT would love to get a set of ebc prolites.