Well first off they are
lousy tweeters, and low powered.
So you are looking for an 8 ohm tweeter, from the DC resistance. These are getting hard to find, as impedances have moved to 6 or 4 ohm. You are looking for an 8 ohm soft dome tweeter with a sensitivity around 91 db, so you don't have to mess with the crossover.
The tweeter is 4.1" but other wise would be a perfect replacement. It is 0.5 db more sensitive, but you won't hear that. The tweeter has about the same cut out. It does not have a lip and the cabinet should have a rebate out to 4.1 inches. So there is a minimal mod, unless you can some how remove the lip form your tweeters and put it on these.
Scanspeak make excellent tweeters, and this would be a significant upgrade to your speakers.