I've just fussed with the knobs and such and can report that using SOX does yield an improvement in SQ.
But, (there's always a but, right?)
This improvement is on the low end of perceptibility and does take a suitably resolving system to be easily noticed.
At least that is what I'm hearing.
And it seems to help in sharpening the focus on each individual 'Voice', in both resolution and inner detail.
JJ