Interconnects and the Speaker Cables for the NAD C356 and PSB Synchrony One B

AQ Jaguar IC's
AQ CV-6 or CV-8 Speaker cables
AQ preamp jumpers

AQ's a safe choice because they sound good in just about any system. You won't have to worry so much when you upgrade your electronics.

Don't be put off by the low prices on these cables. I put those models next to cables that were far more expensive and they were just as good.

The Cerious Technologies Graphene Interconnects and Speaker Cables would work out very well with your set up. The only slight problem is I don't know if Bob (owner of Cerious Technologies) is back up and running.

THANK YOU ALL,
I did try Pangea Audio AC 14 but the highs were rolled off or I should wait longer period to burn in the PC. Or because of the C356 itself (C375 is on the another level).
The best sound I ever heard from my speakers and the NAD was when I used borrowed  Kimber Cable KS1026 speaker cables and the Van Den Hul The Cliif interconnects for the Pre/Amp jumpers and the Elrod PC. I am really grateful to my friend from whom I borrowed the cables because after I returned the cables the sound was disaster so I almost gave up and wanted to sell everything. My friend told me "I told you, don't do it". 
I would be really happy if I could get 10% of that sound.
I believed that the cables make a difference but not like this.