I would replace your paradigm sub with a (used) James emb-1000 (or 1200) for much cleaner, more musical bass.
I would also sell the Monster HTS-3600 AC filter which is likely doing absolutely nothing for your system.....except maybe it looks good....and use that money to buy the subwoofer.
I would also sell the Monster HTS-3600 AC filter which is likely doing absolutely nothing for your system.....except maybe it looks good....and use that money to buy the subwoofer.