Bhobba,
I run the W4S DAC2 with Stealth Indra IC's through a Wyetech Opal pre,to a Krell 300cx with JPS Aluminata IC's, and on to Von Schweikert VR5HSE's using Nordost Valhalla spkr cables. So I do not think it is lack of system resolution that accounts for my --and others -- not noticing any glare or sibilance. Were you using the DAC2 as a pre? Could this have been a contributing factor? Did you try any resonance controls under DAC, or swap input digicable or output IC's?
Neal