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

I'd start with a Naim Uniti, as it has everything in one box (CD, DAC, streamer, FM and Internet tuner) and sounds great, and not just great for a 'receiver.'

Depending on room size, tastes, and second hand prices - Totem Arro or Sttaf, Vandersteen 1 or 2.

Audio Research CD3 MKII
Manley Stingray (original)
ProAc Response 1SC
REL Storm III
Chord speaker cables
Chord interconnects

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.