Still trying to find a new PC

I have been trying to over come the obstacles in the past couple of years  (money wise) to try and find a new PC that will bring out more separation/detail, and help to widen my staging with my current system. I'm using a Classe Cap 151 with ARC CD 3 Mk 2 and Apogee Slant 6s. Listen to mostly; Alt Rock Killers, Grouplove, Sir Sly, Megan Slankard.
Older classic rock The Tubes, Boston, AC/DC, ELO and some new age, Enya, Blues and Jazz.

 Current PC is a Cryo Parts on the CAP and Locus designs Polestar on ARC  Been thinking maybe synergetic, Transparent or Wire World and trying to stay in a sub $600 range with a needed 6.5-7 ft. length Realizing a used selection is probably the way to go), might the forum members be able to give me some good input as to possible choice? Thank you.
Anything Audioquest would be my recommendation.
If you look on Hifi Shark, you should be able to find an AQ Thunder 2 meter near your pricepoint.
I have switched out almost all my cables to the Thunder, as I found it to be a real improvement.
Synergistic Master Coupler, all the way. All day long. However if while searching for your MC you come across a Blue or any other SR PC in your price range do not hesitate to jump on it. Which you will probably find a Blue or other around $500. 

Some of the SR use Active Shielding. This can be a negative if you see it as taking up an outlet. Or it can be a big positive because you can have Michael Spallone upgrade the wall wart which will make an already good PC truly impressive. I had him do that on mine (CTS speaker cables) and it was a huge improvement for the money.
Was there different Master Couplers? I also saw that there was 1 called a designer Master Coupler as well. I've inquired about a Blue though just waiting to find out how much and weather a HC would be  better than just the regular Blue?
They made the, "AC Master Coupler" with and without MPC/Active Shielding, then the "Reference" and- a couple other iterations. ie :
Either the Sockeye or Chinook will prevent any sonic improvement from a new powercord.

Seriously, unless you simply try and buy, it's a lost cause with suggestions. Too subjective. The Agon listings are a great way to get something for 50% of list. This time in particular is a buyers market.

I think the salmon are very cool.