Cables

I’ve decided to purchase some new interconnects and digital cables.   The cable company recommends synergistic research foundation for RCA interconnects, and DH labs D750 coax and DH labs Glassmaster optical.   The synergistic research products are $599 each, I think the digitals are around 300 each. What do you guys think? Or is there anything out there other than this I should consider? Currently running blue Jean products. I had an extra speaker sound, changed out ic between amp and preamp, went away.  Scad was skipping, redirected the toslink.  Went away.  Time for a change.

Bryston cube amp, pre, schitt modi mb, scad cd, aerial 6.