Why not go with a set of subwoofers? SVS, JL, Martin Logan ... just to name a few have excellent products. Make sure that it's a sealed unit with adequate power. Subs have come a long way and may really improve even a very nice system such as yours.
Speakers or Amplifier
Thinking about another upgrade and looking for opinions on if I should upgrade my speakers or amplifier. My current system: Aerial 7T speakers, Jeff Rowland M525, Bricasti M1 DAC connected straight into the M525, and all WireWorld Silver inter-connect, power, and speaker cables. My room is 20' x 26' and treated with GIK acoustics. I listen to contemporary Jazz. My budget is 10K.