How hard would it be to swap the new 03-05 gauge cluster to my zx6r 2001? Would I just need to splice the connector from the new gauge to the old wiring or is it more complex? Anyone done this before?

 

The 03/04 & 05/06 Gauges look the same but are different. The main difference is the speed sensor pickup; 03/04's are on the sprocket cover and 05/06's are on top of the crankcase and take different signals for speed. They are not interchangeable unless you want itto show the wrong speed. Look at your bike and see where the speed sensor is. I don't know if the 01 gauges have digital inputs or analog? Only one way to find out.