Suggestions for upgrading audioquest interconnects

My current system is composed of the following:
Amp: Krell fpb 300cx
Preamp: Conrad Johnson premier 18LS
CD Player: Music Hall 25 with level 2 mods by underwood Hifi
Speakers: JM Reynaud Offrande
All have original power cords. Speaker wire is JM Reynaud biwired. I have audioquset Diamonback interconnects with cardas xlr to rca adapters out of the Krell since the Conrad Johnson only has rca jacks.

I listen to Jazz and blues mostly. I am satisfied with the sound in general but feel I can get more out of my system. I have spent countless hours positioning speakers and furniture and feel I have everything I can get with what I have.

I really feel my next step is to upgrade my cables.

Any suggestions?

Thanks