Need Ideas on speaker cables

Given your system, I would think you would want cables that are on the natural musical side, if so then the best Cardas (used). If your want more detailed the DHLabs. Anti cables have a nice balance. 

It would be helpful if you define the improvements you are looking for.  However, my recommendation at your price point is WyWires Silver (WyWires.com).  Well balanced, solid bass, extended highs, good dynamics, and excellent image density and staging.   
 

https://forum.audiogon.com/discussions/thiel-owners-2

Triode Wire Labs.  Under budget if you need 6 feet or less, $49 over budget if you need between 6 and 9 feet.