Terry is right folks: I've been going over comments and what I heard and I think the "distortion" was a completely different sound than what Archaea described he heard with every speaker but the JTR's, with the former only being heard through the SoundScapes. The amp with the bad transistor likely couldn't handle the SoundScapes low sensitivity drivers, thus it actually did distort or even clip at that time. There was no issue with the right SoundScape, only the left, so that would explain that issue.
The other speakers didn't distort to my ears, though some of them struggled at louder volumes when being run rull range in that large of a room. There's only so much a speaker with smaller drivers can do (like Terry said, we may have been around 100dB or more at the speaker itself). With that said, I heard no distortion from any of them besides the SoundScapes, but rather what I would call driver or power compression, albeit minor. Due to our listening levels it could have also been a soft clip from the amp. However, I suspect Archaea heard what he heard because of where he was seated, which was on the floor, much closer to the left speaker and too close to all of those left speakers. His analogy of hearing two different MP3 bitrates points to a bad listening location; distortion is a much different animal, which usually sounds like buzzing, fuzziness or a whooshing noise that removes clarity and muddies everything up. Since no one else heard that with every speaker except the JTR's (as Archaea says he heard), it was likely his seating location. With that said, at those listening levels the transients could have hit north over 250 watts, and that would have caused soft clipping of the amplifier, which in turn would have been reproduced by the speakers.
Terry, the left monoblock may have had an issue with the SoundScape speaker, but it may not have for the rest...or maybe it did, who knows? I'd contact Klaus and have him look at it to confirm. I suspect the "distortion" heard wasn't distortion but just a bad listening position. The GTG was not a failure, and I really enjoyed it. Everyone will have their own opinions and may have heard things differently than you, me or Archaea. Chalk it up to different biases, preferences and levels of experience, but don't completely blame the amp for all of the "faults" that people found with various speakers. The latter is simply based on subjectivity and opinions, nothing more.
P.S. I shouldn't have to say this (again), but you were a great host; don't let anyone tell you otherwise.