"To a small point, if you’ve work on and modded as many as I have they are very similar, only when you get into the esoteric stuff (non data sheet) like what I and others do with feedback free inplementation stacked AD844/discrete/transformer based I/V stages can you hear a real difference, as for the output buffers again very similar opamps used."
I really don't believe in modding audio components unless there's a really good reason to. My personal opinion is to just buy the right component first. If you make a good choice, there's no reason to fool with it. As far as zero feedback designs that don't use opamps, there's really no need to debate the matter. Of course its a better way to go. Both my Wadia's, Ayre and Resolution Opus are all made this way. Players like that are clearly out of the OP's price range, so I didn't see the need to mention those types of designs.
"To give an example, even the mighty $20k Linn CD12 that I have here at the moment, just has PCM1704 data sheet text book opa627 as the I/V stage and again a opa627 as the output buffer. Just classic dac text book stuff."
From that point of view, maybe. But, as I've stated above, I think it better to look at a component in its entirety, and not just single out pieces. I can also use the Linn CD12 as an example. Its an extremely unique piece because the transport is made by Linn in house. If I remember correctly, its the only CD transport ever made outside an Asian country. I'm also pretty sure the CD12 was the only cd player that transport was ever used. So its really a one of a kind piece, which makes it difficult to compare with other players.