Looking for new speakers for large audio room

I would go with a pair of Paradigm Persona 9H at that price range. Should be a pretty good match with your Pass Labs amps and you may not even need your REL subs in the end. The Persona can be bright if not feed well though so you might have to tweak with your source

pesky_wabbit has it right.

https://www.theabsolutesound.com/articles/atc-scm50-aslt-loudspeaker

Yup, that'll get it.  112db

 Verity audio speakers could be a good match for the amps.. they are quite efficient.

Fully refurbished Apogee Diva will cost around $15K.

JBL S3900s or JBL 4367 and a pair of SVS SB or PB 16 Ultra Subwooofers. Alternatively, the pair of REL No. 31 or 32. Any combination would absolutely do the trick in a 5500 FT3 or 150 M3 room. No direct driver loudspeaker will have the output or directivity control required to successfully fill that room. JBL, SVS, and REL are also likely to have distribution in Thailand. Personally, ivastly prfer thr new JBLs over anything from Klipsch. Succcess with a room that size requires controlled directivity, and that means horns, or possibly a line array. Although the Magneplanar 20.7 with the aforementioned subwoofers and adequate power could be extraordinary - if the room is well treated acoustically.  Direct radiators rarely sound their best in rooms over 70 or so M3 (or2600 ft3) - about half the size of your room. Their conventional cone/dome speakers simply cannot move enough air to generate the levels required, and their broad dispersion means lots of early reflections which will rapidly deteriorate into a muddy sounding mess.