The woofer holes were already rounded over, thankfully. None of the internal bracing was though. Not much I can do about that.
My X-Omni's sound fine as surrounds, but I can't really compare them to anything, as surrounds barely put out much as it is. I mainly was looking for a surround with a built-in stand, which the X-Omni provides. I watched the latest Potter film last night, and the surrounds did a great job, though my listening levels are a bit low, due to sleeping little ones.
I will be putting polyfill in the X-Omnis, but I won't replace the wool. As a surround speaker, I don't want to spend the time or money on a NoRez treatment.