Speaker cables for Egglestonworks Fontaine?

I'm looking to replace my Transparent Audio Ultra XL speaker cables. While they have an engaging and musical warm sound I find them a little dark. Not necessarily a bad thing but I would prefer more high frequency detail and extention. I'm considering Pure Note Epsilon silver cables or perhaps Cardas Golden Reference (two very different cables, I know) and would appreciate any input or other suggestions. My components are:
Classe CP60 preamp w/ Cardas Golden Cross to SimAudio W5 amp. ESP Essence pc on the pre and TG Audio HSRi Squared pc on the amp. Audio Research CD2 cd player w/Cardas Golden Cross ic and ESP Essence pc. Speakers are Egglestonworks Fontaines. Thanks!