Tube amplifier upgrade suggestions welcome.

why ? he knows one answer, at best.
try any number of excellent tube amps by companies with long track records and support: Rogue, Quicksilver, Conrad Johnson, ARC, VTL, Decware, Bottlehead, VanAlstine.......the list is long, i would start w Quicksilver....

The Lore specs from the website:

• 98dB 1W@1m
• 8 Ohm impedance
• 30Hz-30kHz frequency response

So, let's say in the real world these speakers have 94dB sensitivity. You won't need a powerful amp to drive these, especially in that small room. You may have a larger room someday so a tube amp with a minimum of 25wpc will do.
 
You could start by looking through the Audiogon classifieds for a lightly used amp. With a $2000 budget you'll find a larger selection if you go used.

Decware 

Would you consider a used Raven Nighthawk integrated to be a better move than buying, say, the Parasound A23+ new and using my m2si as a preamp?  This is kind of where I'm at decision-wise. 

I ask this particularly as I have (supposedly) very high sensitivity speakers and right now I'd rather have fewer watts that sound better than the other way around. 

A long time ago I had a much better audio system and I know I'm missing a lot when I play recordings that I know really well.  For instance, on Holly Cole's train song I know the person doing all the funny percussion effects moves around the soundstage from right to left and front to back and you can clearly hear that on a good system. 

I miss that level of clarity.  Everything is kind of scrunched up and fuzzy right now, sound wise.  Can I fix that at least partly without spending over $2K? 

Right now I am running Roon to a Chord Mojo, the m2si, and then to the Tektons which I really like.  I really like the Mojo too, actually, so it's the m2si that seems to be the weak link.

@tomic601

why ? he knows one answer, at best.

aww you’re ruining the fun 🤭