Recommendations for 5k upgrade


As winter approaches more time is spent listening so I have allocated this budget for system changes and/or improvement. Planned changes are marked between brackets.

Source:
PC based music server / SB Touch (ext. power supply upgrade, maybe Bolder?) fed into Eastern Electric MiniMax DAC with Dexa opamps. Alternative source: Sony DVP 9000ES CD/SACD via optical.

Amplification:
Conrad Johnson CT-5 with 6H30DR tubes, CJ LP140 mono blocks (tube rolling planned, which 6922?)

Speaker/sub:
Dunlavy SC-IV modded, Velodyne DD-12 or REL R305 (haven't decided which one to keep)

Power Conditioning:
Audience AdeptResponse 12 with e PowerChord (AU24e PC planned, dedicated 20A lines planned with the next room renovation)

Cabling:
IC: NordOst Valkyrja throughout (maybe Valhalla, looking for alternatives with better price/performance), NordOst Silver Shadow for S/PDIF
SC: NordOst Heimdall (probably the weakest link here, upgrade to Tyr2 ? Alternatives?)
PC: NordOst Vishnu to preamp and power amps, stock PCs on other devices (waiting for the final direction for PCs, not sure to stick to the loom theory, having all PCs of the same brand)

Isolation: mostly Black Diamond Racing cones/pucks and one BDR shelf under the preamp, some Stillpoints (planning to experiment with alternatives like Aurio, Symposium, etc, under the devices, maybe some for under the speakers)

Room treatment: just acoustic panels behind the speakers, need high WAF suggestions for my 21' x 30' room which has a half sloping cathedral ceiling and an open staircase. (looking for bass traps that can blend in with the interior for the corners)

I am not unhappy with the current setup but like to have more details without being too lean/bright.

What is my weakest link?

Of course YMMV but appreciate any suggestion to take this system to the next level without a second mortgage (or divorce) and/or improve the synergy between components. TIA!
polyglot
I think you have a very nice, well thought out system and it's because of that I find your quest for more "detail" puzzling. Based upon my experience and what I've read of your components none of them would be described as highly detailed in their musical presentation. IMO trying to change a system's presentation with cabling is fundamentally wrong. It's also a poor value solution. I'm not saying that it can't work, but even if it does it will impede any further improvements in the future.

Before making any changes I would recommend you experiment with speaker placement and acoustic treatments. I believe that in a large room getting the bass right (which probably will sound a little light weight, at least initially) is essential to maximizing resolution and detail higher up the frequency spectrum.
I don't think that cabling is your primary priority. I mention the PC's because they DO make a BIG difference and can be upgraded relatively inexpensively. Improvements are not subtle.
Onhwy61, sorry if my quest misled you. In general, I wanted to take this already great sounding system to the next level -which is what I put on the last lines- w/o breaking the piggy bank. E.g. when I had, IMO, a good system a while back with the CJ PV12, MF2500 and Snell B Minors, I thought this ensemble is darn good...till I upgraded the components.

Placing speakers is a very well discussed and known fact (believe me I did that first) and acoustic treatment, or my specific limitation, has been mentioned already in my OP.
Polygot, I can see why you prefer your new system to the old one, but do you really think getting to the "next level" will be any easier or less expensive than the last major upgrade? The law of diminishing returns starts kicking in quite severely at about the point you're at. Your stated budget will allow for some refinement of what you already have, but I don't think it will truly take you to the next level. Of course, you could prove me wrong.