Suggestions---Interconnects, Speaker cabling

Vandersteen Quatros, Conrad Johnson 250 S, CJ Pre CT 5--currently--running a set of Cardas Golden Ref from Pre to Amp-and Audioquest Niagras from CD to Pre--(tried this the other way around--- the Cardas from CD to Pre, and Niagras to Amp--things sounded a bit muddy.

The Niagras can, at times, seem a bit bright on certain pieces; (In current configuration). Then again, I am also experimenting with speaker cabling, bi wired for the Vandys-

All thoughts regarding above setup are welcome-I know many believe that one has to run all interconnects and speaker cabling from same manufacturer--but not sure I am sold on that idea---