Should I change speaker cables?

I am currently using Harmonic Tech Pro9+ but at time I feel the sound may be a little on the warm side and makes things congested with bass heavy materials. Although I don't know if it's my sytem or the cables but I am think of buying a pair of Nordost Blue Heaven to try out.

System consists of Living Voice Avatar, VTL Deluxe Mono 120, Musical Fidelity Pre24 and HT Pro Silway II.