It is not clear if you are setup for a 5.1 or a 7.1 system? You mentioned "rears" in your post. Do you have "side" surrounds AND "rear" speakers, or are you referring to your side surrounds as rears, or have them placed incorrectly?

For a 5.1 setup, you would have side surrounds, not rear speakers. For 7.1, you would have both in your system.

Anyway, you could go either way. If your sub is from an all-in-one setup, a new sub would make a huge impact for movies. However, the Axiom Qs8's will blow you away and give you a surround experience you've never heard before.

A friend of mine has a all-in-one Yammy system with a small sub and small speakers, he was blown away when he stopped over one day.

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85