PS Direct Stream Vs. Lumin X 1 Sound quality difference?

Note sure what the SFPs were - whatever I could find at my local computer store. I might have to try different SFPs, though at the moment I'm very happy with the X1 and don't really want to mess with it.
I have generally found that ESS based DACs take a long time to run in - but usually weeks not months! I suspect it is the output transformer which is the major difference with the X1 and which takes a long time to burn in.

While I have owned the X1 I have also compared it periodically to my Mytek Manhattan II (also a great DAC). At first - during the first month - I preferred the Mytek. The X1 sounded rather two dimensional and muddled, with rolled off highs. Over time the highs extended, the bass extended and tightened, and the sound stage moved back further and further. The delta with the Mytek became greater and greater. Recently I did the comparison again and the X1 has moved further ahead, with the kind of holographic presentation and sense of realism and presence that it barely hinted at during the first month or two.

My X1 took well over a month even to start sounding good, and really 2-3 months before becoming exceptional. I have had it now for about 9 months and, seriously, I'm sure it is still improving. I've never before experienced such a dramatic change from running in of any component I have had, and over such a long time. After the first month I still wanted to sell it, and now I cannot imagine how a digital component could sound better.

I tried the isoacoustic footers with my X1 and I also found that it made the sound worse - sucked out the bass and lower midrange and made it sound thin. I just leave it with the stock footers.

I also prefer the ethernet input to the fibre optic cable, which I find a little artificial sounding. I use an Uptone etherRegen with a DH Labs ethernet cable which I found did make an improvement. And I also prefer native file resolution - no upsampling.

I have tried it as well. But I prefer native resolution, which for most of my collection is redbook PCM. I find conversion to DSD and upsampling generally to sound a little artifical and "processed". But then I also thought the same thing about the effects of the M Scaler when I owned a DAVE.