As @lanx0003 mentions-
"It may feel a bit rounded or thick." That MIGHT be the result of B series ported cabinet vs modern REL passive radiator design-closer to acoustic suspension/sealed design? Settup/location might fix that.
I use 2 cherry finish REL B3’s with satisfying results. When they die(nearing 20 years), they’ll get replaced with new REL’s.
The fact you have 2 REL’s and not just a single sub is more important to SQ than be concerned about not having current models.
Location/setup is paramount.
If your B3's are cherry finish, I have a home for them. Been longing for a SWARM array. 👍

