minatophase3,
I am currently using a Denafrips Hades preamp, which surprisingly has not been a bad combo with the CODA S5.5. I initially thought it would be totally outclassed, but it's held it's own so far....but yes more performance is there to be had.
I have an Aric Audio Motherlode XL preamp on order right now, should be about 6 weeks out by now (intially 12 weeks)? I spoke with Aric about the 10K ohm XLR issue, which is the very edge of the Motherlode's comfort level....and he is modifying it for me to be good with the CODA's low XLR load.
So far I have not bothered with the stand by as I don't mind burning it in a bit more. I spoke with Doug Dale at CODA, and he said the S5.5s get about a week burning in before they are shipped.