Decisions decisons, speakers or an amplifier

Speakers. Too much spent on electronic upgrades.

I agree that upgrading to 3.6's will give you more bang for your buck than an amp upgrade.

If your room can handle them, 3.6's

I don't know much about the Parasound. My personal approach would be to upgrade the speakers to something that will benefit from every upstream upgrade for a while, and I think the 3.6's would do that. My guess is that the Parasound isn't sufficient for them, but that buying them first would give you a serious "Wow!" factor, and that future upstream upgrades would provide continued smiles.

I haven't ever had a pair of Maggies, but I've heard many references to them working extremely well with Acoustic Research amps. As always, so much depends on your room size, acoustics, and musical preferences.

The point brought up by Kthomas is important 3.6's need power to shine.
They are big and need space to perform properly.
3.6's will provide you with much better bass and if in the future you can also upgrade amplification you might be surprised with them in this area. (Not their forté, but good)

A fellow audiophile has 3.6 powered by Rogue M-120 monoblocks in a large room and sound very good. Source is Northern Star transport and DAC