Also note, there were two generations of 9 speed that don't work well with each other. Cassettes and chain are the same, but the derailleurs and ergos are different. Basically the older version has all alloy rear derailleurs and the newer version RDs have carbon bodies. The shifters have different index gears. You can use 10 speed RDs with the newer 9 speed ergos. You can replace the index gears in the shifters, making them old 9, new 9 or even 10 speed. Let me add, I find the 9 speed Campy is/was the best shifting system they have/had.
BTW: this ^^^^^^^ goes for Record and Chorus. I'm not familiar with their other levels of components.
Last edited by gearbasher; 07-29-21 at 08:48 AM.