I have owned both Divas and Full Ranges modified and re-conditioned by TSW. The Divas were originally bi-amped, and then, at Rich's suggestion, I used his passive crossover and single amped them--he was right, they were better that way. I used both tube and solid state amps, and preferred the tubes, and they had no trouble driving the Divas, so rumors about a nasty impedance curve likely are not true.
I now have the Full Ranges. Again, Rich has modified the crossover, so it is passive, and the speakers can be driven by a single amp. I am using them with ARC VT 150SEs, and do not find the combination lacking in any way. Rich is currently modifying the crossover for me (he called me to let me know that he had come up with an improvement) and I assume, as has been the case with all his upgrades, that the performance increase will be noticeable.
I now have the Full Ranges. Again, Rich has modified the crossover, so it is passive, and the speakers can be driven by a single amp. I am using them with ARC VT 150SEs, and do not find the combination lacking in any way. Rich is currently modifying the crossover for me (he called me to let me know that he had come up with an improvement) and I assume, as has been the case with all his upgrades, that the performance increase will be noticeable.