1): signal path cables - yes, better EM shielding, better match to audio analog/digital path impedance, better connectors always helping me to reduce noise, and to flatten freq response.
2): power cables - nope, clean, not oxidized over time, looking fresh, power cable' provided by manufacturer is fine, technically nothing can be improved. If cable is tool long, I cut cable and use professional grade plug. As for phono-pre or other separate's cable, you may use ferritic EM filter clamp to put on cable, which will reduce significantly AC power line. Good filter clamp reduces noise in original cable by 60dB or more (x1000 less noise), and it cost nut much, In many cases replacing aged wall outlet, and resistive fuses in the house AC power distribution is helping to reduce power drops. Try to avoid ground loop in hifi setup, if hum noise can be heard from speaker.