Just installed the Plixir Elite 2-tier 4A BDC + BAC 150 into my system. The BDC powers my custom-built htpc, BAC powers my DAC and a separate LPSU.
Please note these components were previously using the earlier generation of BDC and BAC. The differences from stock should be even greater.
Ok, first impressions of the sound I.e unit not burnt-in yet:
Overall improvement: the differences were easily discernible and not merely incremental. Instruments not only sounded more natural, they actually sounded "different". I use "different" to highlight its not more of the same sound, but the improvement may have actually made reproduction more accurate or closer to what the instrument actually sounds. This was apparent with the starting of Jennifer Warnes - rock me gently.
Soundstage: location of instruments was portrayed more accurately. You didn't have to strain so hard to figure out where they were located. Depth extended further back, foreground remained roughly the same. What surprised me was the addition of soundstage height. This was not apparent previously, but I could now tell that vocals were presented on a different plane than the instruments, where the recording had such Info. Low drums tended to sound lower, high hats and bells were higher, relative to the vocals. The overall soundstage was also raised slightly.
Vocals: Presence of the vocals improved significantly. Voices came out larger than life (which I like), more immediate, more detailed (can hear inflexions and breaths more easily), yet more natural at the same time. A side benefit of this is that I can listen at lower volumes and yet feel the same level of involvement with the music.
As usual, YMMV. But for the plixir elite to have made a significant difference to what I believed was quite an optimised setup already, I was impressed and pleasantly surprised