Travis,

I have a spreadsheet that has the cross reference in it.

It looks like the 03 ZX 6 uses the same filters referenced above. Use the longer filters if you can, as they have more filter material in them, but check to make sure you have adequate clearance first. If I remember right the ZX6 filter is on the front of the engine behind the headers, there may be limited clearance there.

Check my earlier post of a full cross reference to filters that will fit your bike.

Scott