Pass....Accuphase....or......

Your room is almost the same size as mine. Last year I briefly owned the Parsifal Ovation, great speaker BTW. I have my doubts that the XA25 will be enough. It depends on what you listen to and how loud. The Parsifal is a pretty demanding speaker IMHO. More (and quality) power will be rewarded.

I had the XA-25.  It is really good and will replace 18 Wpc no problem.  I used it with 50W min speakers.  There were a rare few recordings that would clip the highs momentarily at loud levels and I sold it.  That was a mistake.  I now have Corwalls driven by the Pass Int-25.  The XA was in another league with a good tube pre.  It was neutral, no sound of its own, and never sterile.  I found the bottom octave very well defined but weak.  A REL sub blended transparently and it was truly Really good.   Impressive dynamics, noise floor and drive.

The XA-25 is one to audition then. The Parsifals can produce big amounts of low frequencies in my room depending on placement so maybe they work fine with the XA-25?

I wouldn't rule out the Accuphase, but I would give it a listen before buying. Some people do feel that Accuphase is polite, but to me it is just very low distortion.  

As far as matching with your speakers, Accuphase claims to double down to 1 ohm..  The December 2023 Stereophile has a review and measurements of the A-300, which is not exactly what you want, but may be helpful.  The A-300 also was named Amplification Component of the Year in the December 2024 Stereophile.  Don't count it out without hearing it.

Like I said above, probably not enough power. Make sure you can audition before purchase or buy it used.