Your room is 16×20 = 320 ft².
Focal recommends the Sopra 2 for rooms as small as 320 ft², and would be ideal for larger rooms up to 750 ft². The Sopra 2 has two 7" woofers and is 46⅞" tall with a footprint of 14×21". Weighs 121 lbs.
Focal says the Sopra 3 will reveal its full potential in larger rooms measuring up to 860 ft². It has two 8¼" woofers and is 49¾" tall, with a foot print of 15×23". Weighs 154 lbs.
Both speakers are of similar sensitivity, 91 and 91.5 dB, with similar bass performance. The F3 frequency of the Sopra 2 is 34 Hz, and it's F6 is 28 Hz. The Sopra 3's F3 is 33 Hz, and it's F6 26 Hz.
Compared to the larger Sopra 3, the Sopra 2 is 3" shorter, with a smaller footprint, and is 33 lbs. lighter. Mind you 121 lbs is still quite heavy.
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I haven't heard either speaker, but Focal recommends the Sopra 2 over the Sopra 3 for a room of 320 ft². I'd be inclined to go with that. As a guess, I think the Sopra 3 might overwhelm your room.