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.
Foundation relative to Blue Jean will be a revelation. My current Synergistic is well beyond Foundation level but I've had a lot over the years going back to the early 90's and they are hard to beat. The Synergistic house sound is big and full, detailed and dimensional, with superb imaging and a very smooth balance, no sonic trait exaggerated, none missing either. As you go up the line you simply get more, and more, of everything.  

Kemper Holt, I think it is, after buying Tekton Moabs did his whole system in Foundation and is very impressed. Pretty sure there's a YouTube review he talks about it, might be with his Moab review. Search around. 

Since you're talking with the Cable Co I would ask them to describe how they think those different cables SR and DH compare sonically. That's really all I ever go by. Skip the tech talk, spare me, just tell me how it sounds. All that matters. If you like what you hear when they describe it odds are you will like what you hear when its plugged in.
If you’re speaking to Cable Company, why settle with SR Foundation and DH Labs Digital, ask Peter to send you 2-3 brands of analog and digital cables. It’s your system and your ears, don’t let anyone else decide or tell you what would sound good in your system.