My guess re: the 160 is there wasn't a lot of demand at 160, so there'd be less at 250. So they just eliminated an unpopular option, making it so they could save on inventory expenses.
Non-sequiter much?
That is quite an amp...
Bigger soundstage and more distant are the same thing, in my experience. You mention sibilance n the ms2s and say it's similar to the 225s, but don't mention sibilance ont he 225s. Do you mean on unmodded 225s?