Life after Polk LSI15's---SUGGESTIONS

Having recently upgraded my Odyssey Stratos amp to a Jim Nichols custom tube amp (which is awesome) and my AVA DAC to a Monachy NM24, which is also superb and offers the flexibility of a SS or Tube DAC with a line amp, I'm now finding that the weakest link in my system are my Polk LSI15's. I'm looking for a little more air on the top end and a better defined bottom end without giving up their glorious midrange, warmth and spaciousness. I would appreciate any suggestions up to $2,000.00 I would consider stand mount or floor standing speakers. Whichever would give me what I'm looking for. Thanks for your suggestions.