If you had 6K to build a system with used gear?

Digital only, right? Everything used.
Devore Super Gibbon 8 speakers
Rowland Coherence I preamp
Rowland Model 5 power amp
CEC belt drive cd-player
Purist Audio cables and power cords

Anyone should be able to do this with relative ease.

Merlin VSM, Audio Physic Virgo II, Quad ESL57, or Fried Studio V loudspeakers - it depends on your tastes and what's available at that time.

Deja Vu, Jadis, Dynaco, Audio Note, Rogue, or Quicksilver amplification. Getting an integrated will definitely save you some cash.

Audio Note DAC with a cheap (maybe a $99 Samsung or something like that) universal transport, Sony SACD player, or a Music Hall or Rega CDP. I much prefer the DAC route, as it insulates one from the achilles heel of audio - CD player transports.

For myriad reasons, I'd advise staying away from Chinese kit to the greatest degree possible. No need to spend for power conditioning, as it often robs the system of muscle and/or emotion. And, don't go crazy on cables; get copper stuff that will complement what you have and where your tastes lie.

Hi, I also have an Ultimate. An amazingly versatile unit. Any manuals or upgrade suggestions? Thank you.

McCormack DNA 225, Promethius Ref 4 TVC, Magnepan 1.6QR, and a ModWright modified Oppo 95. If you could go 6K, you could probably get a new ModWright Oppo 95. This may look like a head scratcher to anyone who hasn't heard Dan Wright's stuff. Anyone who has will understand.

Jeff Rowland Concentra-2 $3k-$3.5k without phono
Primare CD-31 $1K
Revel-Performa F30-F32 $1.5-$2K

If you want to allocate more $$$ on cables a Primare I31 could be implemented. This system will gave you dynamics-neutrality and bass below 40hz.