I have not yet upgraded the tweeters. I am waiting to see if Kharma comes out with something new next year. I am fortunate to live only about 45 minutes from GTT's location, and Bill was kind enough to pick up and drop off my speakers for me in his van. I would imagine shipping would cost a couple hundred dollars (too heavy for Brown). All internal wiring and the crossover itself was upgraded to Enigma, and a new bottom plate was installed.
As to the sonic changes, they are amazing. The speaker has greater transparancy, life, speed, rhythm. Bass is tighter. Midrange is smoother and the transition from bottom-end to mids is now essentially flawless to my ears(there used to be some sort of upper bass hump). But the most impressive change is in the upper register, where everything is cleaner, clearer. More extended without any "hi fi" etchiness. Soundstage is broader and deeper. There is an immediacy that was not present before and that rivals anything I have heard anywhere. As I said earlier, it's like a veil was lifted from in front of the speakers.
Call Bill at GTT; I'm sure he will be happy to discuss cost, logistics, etc.
