I used to own some Sonic Frontiers gear... I understand you quandary. It can sound pretty warm and so you have to walk the line of getting a pretty neutral interconnect. I have to agree that moving up the Cardas hierarchy will get you more transparent sound. Used, would be a good way to go. Get into the Cardas Clear or Clear Beyond lines would be your sweet spot.
RCA Interconnect recommendations
I'm looking for a new set of interconnects and need recommendations. I'm running a Rega P3 (with Exact and Neo PSU) and a Sonic Frontiers SFL-1. In between, I will be adding a Darlington MM7B, which is on order. I was using an old pair of Cardas Ultralink 5C interconnects but find them a bit muddled. I also have a pair of Audioquest Red River interconnects and they're very bright. Any suggestions for something that's musical, clear and detailed, with good bass response?