For what it's worth, after I had my T90 recabled by @PETEREK, harshness became virtually nonexistent. It was much easier to listen. I don't know if that's because of the higher quality cable he used, or the fact that it was balanced, or both. I imagine the better quality cable helped.
Same experience here. Although, I know for sure that Forza Audio did some mods other than just re-cabling, as Matt was asking me about some particulars. I told him to make it neutral. I do have to ask what exactly he did, but he did an outstanding job.
PETERTEK, that was the one I meant in my post. I've seen some spectacular pictures of modded T90s. Seems to be a very capable business!