I love the scientific talk of why one Amp might be better than another and if money was no object I could see this discussion going on forever, some for and some against. Without more information though (budget) I will answer as to my personal experience and limited amount of funds. To start out I assume that you have one of the original PSB Stratus Gold's as written about here:
https://www.stereophile.com/content/psb-stratus-gold-loudspeaker-specificationsThe set from the early nineties does dip below 4 Ohms but does not go below 3 Ohms and should be no problem for most well respected Class D Amps.
The later set though from the late nineties does dip about an Ohm lower and in a lower frequency range making these I would say, harder to drive.
I have Tekton Double Impact speakers (I did purchase the upgrade package and the 4 ohm version) and though there is not an awful lot of information out there on the impendence curve of these speakers I have found them hard to drive at mid to high volume with the limited amount of money that I have to spend on this hobby. I finally settled on the Peachtree Nova 300. It sounds fantastic and is in all in one box unit that is rated into 2 ohms. I can now crank it loud enough that you can here it inside my neighbors house and it runs somewhat cool. It will get warm with prolonged high volume listening, this leads me to believe that these speakers demand more current than we are lead to believe. If you are worried about it just step up to the the Nova 500. I have found many places that will let you do a free home trial or in some cases just pay the restocking fee if you do not like it. I would say for the money they are hard to beat with versatility and sound from a "1 box does it all" stand point.
https://www.peachtreeaudio.com/collections/amplifiers/products/nova500