Speakers or amp to be upgrade?

"Speakers are the one and only thing that will make a major change for your system! Everything else is of secondary importance!"

Completely untrue statement.  A system can be shaped in many ways.  It comes down to what you are hearing and what you would like your system to do.  For example a preamp can add dimension, micro and macro dynamics, detail, extension, focus, separation of vocals and instruments, with more impact that some speakers can.  So can a better source DAC, ad amplifier.  How did I form my opinion, well easy, I have taken various components and placed them in various systems and the impact for the component has been the same major change.  The only difference was the speakers, etc.  In performing component upgrades, people were also able to hear the impact that they also can add to ones system.

Happy Listening.

Speakers first!  Always!!!

So, you have 3 systems setup?
Does your list order indicate the speaker/amp match up?

If you don't want to change the way your speakers sound now, it's pretty simple.  You don't need to upgrade anything. You either want to change the sound, or you don't.

It’s not about opinion. You change up the weakness in the chain. What will bring the band closer to standing in your room? Right or wrong not opinion. Stay focused on delivering to your ears exactly what your source provides. Everybody wants to change the sound to something they initially like better but over time your brain knows what is real and you will listen longer , louder if you stick to the path. No opinions! 
 I have observed over time that for many the preamp, the brain, or control center is there weak link.