Overall I am really happy with my system. Sometimes I just feel like I could get more bottom end but...my sub's pretty darn good!
You can do better, but I suspect you would need a very significant upgrade like the EP800. If you are not in a hurry, save your pennies and upgrade to the EP800.
This is the situation I am stuck in. My appartment gives me a big low end boost so my EP350 plays flat to 20Hz. To hear an improvement I would need a sub with significantly more displacement, like the EP800.