I've never replaced a driver, but the two biggest tweeter/high freq. improvements one could obtain (aside from component upgrades) would be to:
1. aquire a performance-oriented racking system that applies the appropriate vibration handling methodology (along with associated peripherals).
2. Install proper AC line conditioning for each of your components.
Considering that your tweeter is probably better than average sonic quality already, if you address 1 and 2 above, you will most likely extract far greater realism than most any tweeter replacement can provide you.
-IMO