And as far as the new tweeters are concerned... Take one speaker, and out in a new tweeter. Leave the other one with the old tweeter, and do blind tests to determine if there is an audible difference.

The one caveat on this: Does the new tweeter have the same performance characteristics.

Better to do it with a pair of speakers... Take a pair of M-22ti's.... run pink noise through one for 100 hours at a high level. Leave the other new. Have someone else hook up both speakers on identical stands about 12-15 feet from you... and next to each other.

Listen to music in mono, and switch back and forth between the two for as long as you want... and chart the results... as long as you are honestly doing a blind test... you will have an answer.