@jpidrovo
I've had Klipsch speakers for about 15+ yrs now the main difference is the woofers the reference woofers are made up of plastic mixed with something else.
The premiers woofers are alumium covered with ceramic coating, maybe also different cross over Im not sure.
As roberjerman said if you dial in placement correct you wont need a center I do have one for movies only not 2 channel listening. Hope this helps.
Keeping Rocking 🎶