you are in a tough spot.the power cords is the least place where you are going to hear a difference.
the hiearchy for cable is;
interconnects (compenent then pre to amp)
i agree with you on the cardas house sound, it is lacking on the image specificity and detail.
you could experiment with changing one interconnect - try between the source to amp. i have found the xlo signiture 2 to be a very transparent and fast cable and have used it in combination with cardas interconnects with good results.
dont be afraid to mix and match your interconnects, i tried all cardas, xlo, tara and transparent. the best result i got was the cardas between pre to amp and xlo beteen cd to pre.
most interconnects fall in the 2 camps:
1. warm / bloom / body ( ie. cardas )
2. fast/ imaging / revealing (ie. xlo)
despite many different opinions- there is connection between price and performance .
i have taken home cables from the same manufacture and have gotten the best results from mixing a "warm" cable with a "fast"cable. please keep in mind, that is my system.
hope that helps !!!]