Power cords known to work well with ARC geare are Sain Line, Shunyata, and Synergestic Research. I have heard good things about Wireworld and Transparent but don't know anyone who uses them. ARC uses Sain Line and Shunyata power cords and cables in their listening rooms. They also use Shunyata VTX internally in thier Reference gear.
I chose Shunyata Alpha HC for my ARC gear. But that was a few years ago. Sane Line was slightly better but much more expensive. I have had both ARC Litz cable and Synergistic Research in the past.