Just for the record,
Keith O. Johnson is NOT the same person as Lew Johnson of Conrad-Johnson.
Who by the way is not the same as William Z. Johnson of Audio Research,
and neither are involved in Johnson&Johnson...
Spectral is a class in itself, not at all on the same level as Naim, Burmester, T+A, as mentioned in an earlier post, as well as for almost all other brands for that matter, save for maybe Krell, Goldmund, Levinson, and maybe a couple of others in this stratosferic territory.
What I mean is, it's THAT good.
Mixing brands at this level is certainly a possibility, just to come to the sound you deem "perfect" for you in your specific situation. Just be sure everything is of the same top level, and have deep pockets.
I've had the chance to listen to Lyra Connoisseur's 4.2 SE preamp on Spectral's DMA360's for a week and that was absolutely astonishing. It rewrote my reference for neutrality, transparency and dynamic linearity, which are just words that say that for the first time I essentially could not pinpoint the sonic character of the preamp anymore. As if it was not there! As if there were no restrictions anymore in openness. Like the cliché that the veils have taken off, but this time they were ALL taken off and suddenly you're looking in the face of the musicians.
Anyway, this kind of stuff is worth the search,
hope you enjoy it when you've found it.