High Level Distortion

I find it hard to believe that cables, tweaks, or room treatments would produce the distortion you describe. BTW, 88 dB is not very loud in real world terms so I have to suspect some faulty electronics or a blown driver in your speakers. Play at a moderate level and put your ear close to each driver to see if one is blown. Unfortunately, the only way to isolate an offending electronic piece is by substitution...

Do you have a buddy with some equipment to loan you for trouble shooting?

Thanks, I've taken that approach already. The drivers aren't blown, but it wouldn't likely happen on three speaker systems, in any case. And I have several amps, several speaker systems.
However, since then, the harshness seems to have gone, which leads me to the conclusion that something in the system (either the Valkyrja or the First Sound) were not fully broken in. Unfortunately, I cannot determine which one was the culprit. I left the room, with music playing, returned an hour later, and no only was the harshness gone, but the sound had transformed, like Cinderella after the Fairy Godmother waved her wand.
The instruments were actually larger and the musical lines were much better. Instruments had body to them, and the stage itself was vastly larger than before.
All this over the course of an hour?!?!
I just wish I could pinpoint which component was the culprit originally. The First Sound Presence Deluxe Mk II had only arrived in my home 10 days ago and I was still breaking it in, although Emanuel Go suggested that it would be broken in after a week. However, he did, in response to my question, indicate that the volume used for break-in was a factor. I had kept the volume at normal conversational levels due to an ailing parent, so perhaps it hadn't fully settled in.
The Valkyrja arrived around the same time, and I don't know about its break in time. Since I bought it on Audiogon through a dealer, and the dealer didn't know how long the previous customer had spent breaking it in, it's possible that the cable was responsible. Roy Gregory, in HiFi+, indicated that the Valkyrja took around 400 hours to break in. However, a call to Nordost yesterday got a response of around 100 hours to break in. Who to believe, Gregory or Nordost??
Things sound heartbreakingly moving now, so all's well that ends well. A belated Christmas present, but one I'm happy to have received!

...did I mention....isolation???
I had originally had the Hurricanes on two platforms hardly isolated enough. I borrowed some Zoethecus amp stands from a dealer, after I'd deduced that the amps might be vibrating and throwing off distortion.
Voila! on the Zoethecus stands, the distortion all but disappeared! I say "all but" because the Hale Revelation 3 speakers tend to become a bit distorted and grainy at peaks. It just goes to show that the isolation platforms -- which were okay in the basement because the concrete floor seemed to agitate the amps less -- can affect the sound tremendously.
I was reminded of the importance of isolation when I was re-reading an article in TAS, back in 1992, where HP reviwed, along with Michael Gindi, the Forsell turntable. While Gindi found no flaws with it, HP had averred that the bass was "slow" and rounded. Gindi, upon a hunch, removed his turntable from the 250 lb granite stand and put it on a very sturdy table,and, as he put it, voila! He got "slow and rounded bass" exactly as HP had said.
So, isolation is another important factor. I'd "done" the room with resilient channels and ASC's IsoWall system, but neglected the amp stands (although the equipment stands are Billy Baggs [good, but still not the best in terms of isolation -- the Zoethecus are MUCH better] as the culprits.
As I am very aware "everything makes a difference!"