Speaker cable advice

I am currently looking for a new pair of speaker cables.
My current setup is a pair of CARY SLM 70 tube monoblocks, a counterpoint sa-3000 preamp, cal icon mk2 power boss, rega planar 3 with an rb600 arm with a denon 103 cartridge and PSB stratus goldi speakers. I am currently running morrow ma2 ic's (great cable by the way) and audioquest type 4 speaker cables biwired. My budget is around $500, and I only need about 4 foot runs. I am considering goertz, kimber, xlo, etc. I would like them to be biwired
Any suggestions?
Thanks