Thanks all for the great suggestions and nice comments!
Source: Since I am focusing on playing FLAC files (still have to restrain myself from getting a TT -not talking about an Audi- as I know the total cost will soon exceed the cost of a new sub/compact car), and rather using the SACD/CD player occasionally (therefore I don't see the need for urgent upgrade; except maybe to a bit higher level like the Sony 777ES series).
I will look certainly into a better DAC and digital cable.
ICs: just bought the first pair of Valhalla ICs so will soon experience the difference.
SC: thanks for the confirmation of the Tyr2 that I was trending to. Glad to hear that this is not my weakest link.
PCs (your advise needed): In a forum they mentioned that Lars, the NordOst rep, demoed a system with (just) one Valhalla PC between the wall and conditioner, the rest of the system just had their entry level PCs. Lars stated that this setup is better than, say, all Brahmas throughout the system. The audience (no pun intended) concurred after the demo. If one follows this strategy, I would upgrade the AdeptResponse PC to AU24e first (it is what I put in my plan).
I would appreciate if anyone can confirm this strategy/philosophy in getting the very best PC upstream and leave the rest on entry level (or maybe stock cords?) to achieve the best price/performance. (I really wish not to need to end up with Valhalla -or equally priced, even used- PCs- for every device in the system.
Also, I will keep looking for the review on game changers in this area. Just looked very briefly at Cabledyne's website, the PCs looks decent.
Pconditioning: Even though I had great experience passing from a NordOst Thor to AdeptResponse 12, I will not likely upgrade to the newer T series before the source and speaker and power cables are upgraded. Rationale: if I shell out another 10k (or 5k for the upgrade) from the 12 to 12T, I might as well contemplate replacing the big Dunlavy SC-IVs to something at least good sounding but more appealing to look at.
As mentioned before, I will upgrade to at least one dedicated 20A line and ask the electrician to put more than enough earth poles to ensure I have the best ground possible, which I believe will eliminate potential ground issues.