10' speaker cables

Good ol' 12 gauge twisted duplex zip cord. Low resistance. Great conductivity. Ten feet will set you back a few bucks if you buy in bulk. Put some heavy duty spade connectors on and you are good to go!

And you can repair your lamp cords with it!

I've been using Audiomica Labs cables and find them wonderful, very even top to bottom with great detail and decay. This one in particular is super, the Genimedes Ultra Reference. Since Audiomica hand makes their cables you can get them in any length you require.

https://audiomica.com/genimedes-ultra-reference

I used Audience AU24 cables from my Ayre VX5 Twenty to KEFs before with excellent results.  I have a friend with the KEF Reference Ones and he uses Luminous Synchestra cables between them and a Java Double Shot integrated.  Really sounds nice.    

Transparent Music Wave or Cardas Clear Sky. The later will be slightly more musical and warm. The Ayre is very natural and musical the KEF can be a bit detailed so the bit of warmth with the Cardas would probably strike the balance. 

Given your components a reasonable budget is around $1K to get the most out of your system... assuming no weaknesses upstream.