Subwoofer...one more sale?

I'm very happy with the most aspects of my system but want to hear the low organs in some Pink Floyd or the trance level bass in some techno music.

My issue is that I really value soundstage, timbre, etc. You know, all the things $3000 power conditioners and attention to cabling can bring.

Am I dreaming to believe I can buy a DD15 or Rel Stadium III and be satisfied, or do I need to buy two subs, or am I going in the wrong direction?

Have JM Reynaud Emeraude, ARC REF gear, Nordost and SR cables, Ayre CDP, VPI table.

Thanks!