Which cable to change first-intercon. or speaker?

My system consists of an Audio Aero Capitole MkII CDP directly feeding (balanced) an Audio Research VT100 MkII, that drives my Von Schweikert Audio, VR4 GenIII SE's.

I want to upgrade the cables in my system, but I don't know which cable to upgrade first, the speaker cable or the interconnect.

So, which cable should I replace first, the interconnect or the speaker cable (and why), or should I plan upgrading both together?