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.