synergistic des. ref vs nordost Valhalla

I have a system of interconect cabling consisting entirely of synergisitc designer reference with active shielding; speaker cable is FIM gold. The electronics are CJ art, dcs gear for digital and krell 650 monoblocks to JM LabsUtopias speakers. The system sounds great as you might imagine. At the recent home entertainment show I lsitened to a demo of Nordost Valhalla speaker cable and interconnects that made a very inexpensive system make MP3 file sound excellent. Has anyone got any experience comparing these cable systems? I am obviously reluctant to move from an expensive investment in the synergistic cable. My listening experience and recent reviews lead me to believe that the Valhalla may be a breakthrough product worth the trade.