In a lot of places in the U.S., it's hard to build a utility closet for $65k these days -- that sounds extremely optimistic for a dedicated room. I have a close friend who lives in a low-cost part of the country and his dedicated room is coming in around $200k. The idea is right on the mark, however. You'll get dramatically better sound -- absolutely no comparison -- by building a well designed dedicated room and going with a much more modest speaker, as opposed to putting a state-of-the-art, $135k speaker in a regular room.
As for X-2's specifically, whether it will "work" in smaller rooms is beside the point. It is absurd to use a speaker of its abilities in anything other than a purpose-built, dedicated room, with anything other than state-of-the-art componentry, and without giving it the very best set-up job. It's like owning a Ferrari, but putting a $250 set of tires on it. $135k speaker in a regular room? ... You know the answer.
As for X-2's specifically, whether it will "work" in smaller rooms is beside the point. It is absurd to use a speaker of its abilities in anything other than a purpose-built, dedicated room, with anything other than state-of-the-art componentry, and without giving it the very best set-up job. It's like owning a Ferrari, but putting a $250 set of tires on it. $135k speaker in a regular room? ... You know the answer.