Which to Upgrade first? My Amplifier or Speakers?

Surely the speakers as they make more of a difference to the sound. you can then get an amp that is matched to those speakers.

The first frequency to drop out with volume is bass response.  Consider buying 2 REL SHO’s.  They will create a wider sound stag.  They will also allow you to hear bass at lower volumes.  REL’s high level connection also helps the subwoofers to play like woofers.  The volume needs to be about 40% and the crossovers set at right frequencies.  I think most people play subs way to loud.  This is also why playing two is better than one.  Pushing air more evenly and balanced really improves sound.  I am not a big fan of Maggie’s.  I hope you listened to other speakers as well.  It is all about what sounds best to you.  Good tweeters can also bring out more detail.  Most of us also have hearing loss in higher frequencies.

there are really knowledgeable people in this group.  A great place to get ideas.

"Good tweeters can also bring out more detail.  Most of us also have hearing loss in higher frequencies."

 I have come to the conclusion that until your HF is right the whole spectrum of sound you hear will be off. I don't know how it works but the right HF gets you better bass, snappier drums and percussion even below the crossover point. HF does magic to the whole speaker and until you hear it the first time you have no idea that was what was missing in most setups I have heard.

if separation between instrument lacking just upgrade speaker if not upgrade amplifier  ,,  easy as a . . . .

Before you make huge expenses which could have sideways results:

First, do you have a dedicated line (I do), proper power line conditioner (my CorePower 1800 is great) and then there's power cords which can make or break your experience

HTH

Why not both at the time time and be done with it?

Do the same as so many pro studios and go ATC active.

What cans are you listening to?