Which to Upgrade first? My Amplifier or Speakers?

Norman, don't let yourself be too impressed... : )

Since you can only upgrade one component at a time, given that the Maggies are harder to drive...if it were my choice, I would start with the speakers.

Reason being: the Maggies will force / restrict amplification choices should you keep them and choose to upgrade the amp first.

For speakers, I'd narrow it to a category of speaker type. Since you have had electrostatic and panels for nearly 17 years, perhaps be open to another speaker category.

Personally, I recommend higher efficiency speakers...they will offer you a much broader amplification palette to choose from. And should you choose a higher efficiency speaker you can enjoy them with your McIntosh amp until you are in a position to replace it.

FYI, Maggie 1.7s driven by a McIntosh stack are one of my favorite (top) local audiophile systems. 

JanZen has a hybrid dynamic/electrostatic in your price range that has gotten excellent reviews!

So what I’m reading, you love your amp, you love your speakers, you love your turntable, and you really love your new phono stage.

For good reason, I would say. Those are all really good, highly regarded components. Congratulations!

Now the bad news. Being so good makes it really hard finding replacements that will be true genuine upgrades and not merely different but around the same level.

The easy way out (for me) is do like everyone else and stick to your literal question only being me answer it better with get Tekton Double Impacts or Moab or Ulfberht something like that.

But that would be doing you an injustice. You got a nice system. No wonder you love it. What you want I’m guessing is more of what you just got with the phono stage.

The good news is the price range you are in will get you the newest and just about the best Synergistic Research interconnect and speaker cables, Atmosphere Level III Euphoria. Which if you think you love your new phono stage, wait till you hear these! Absolutely guaranteed to rock your world. (Literally, guaranteed: all Synergistic come with 30 day guarantee.) Plus maybe even have $$ left over for a full complement of PHT, ECT, HFT and some Orange Fuses.

Or just get the Ulfberhts. http://v2.stereotimes.com/post/tekton-design-ulfberht-loudspeaker/ Either way, you can thank me later.

Go listen to different speakers and amplifiers.  Let your wallet and ears determine what to upgrade, if anything.  I've had the same dilemma, so I started by listening to speakers. Everything I prefer over my current speakers were way out of my price range,  so I kept my speakers. I'm still in the process of listening to different amps and preamps. 

If you still really like the Maggies, get a Sanders Magtech amp to drive them. Or, get a pair or quad (swarm) of good subs to augment the 3.6’s. Getting the deep bass out of the panels will make the upper-bass, midrange and up cleaner.