The most important factor in soundstage imaging

Breakdown on imaging:

80%: The speakers, you want smooth and well-controller off-axis.

19%: Room placement and treatment

1%: Gear; the only way an amp or whatever can affect imaging is will poor channel balance and channel separation (crosstalk); if you paid over $300 for a stereo power amp and it has poor crosstalk (~30dB), it’s junk. Even the $350 Crown 1502 amp (meant for PA, but some use for subs and speakers) has >55dB or separation at all frequencies, that’s lower than the hearing threshold for THD.

Buy what you can afford.  Choose your room.  Set up system. Put on some primo tunes.  Move speakers around until they sound awesome.  Sit back and enjoy.  Avoid neurotic tendencies.  Oh, have a beer (insert favorite drink here)!!

@tomic601. You're right, I can't believe I forgot that! Shame on me, and thank you for the reminder and kind words. Great to hear someone else is getting the results and satisfaction from that book the way I am. 

@whart :    "Even with a good system, well set up in a room, a lackluster recording, mastering, etc. will sound very disappointing"

Agreed and wonder why this isn't always mentioned first. As I understand it, to have a good sound stage there has to be intention on the part of the engineers/producers. If they don't make that effort and know what they are doing then sound stage will be lacking or if not lacking, a matter of circumstance. And it seems like tweaking a system using a poor recording would be frustrating and counterproductive.

So it seems like the first point of advice would be to start with a good recording. I've got The Who's first album. It is in mono. It is not my sound stage reference recording.