I installed in walls for years. None of them, repeat NONE of them sound as good as a "box" speaker of 35% the cost in terms of tonal accuracy, soundstaging, bass performance (accurate, not just bass volume).
I echo the advice to build in-wall enclosures for whatever you ultimately choose, and suggest you do so with the input of the speaker manufacturer-- if it's a high end inwall they've been asked and have answered this question, or should at minimum be able to point you at an installer who can give you some pointers on real-world implementation of that model.
Contrary to most "box" speakers, response contouring switches on most inwalls, when properly implemented, are a good thing to help you deal with the nasty acoustics. Parasound also makes (or made) an affordable mini EQ suitable for insertion in a tape loop or between pre and amp with parametric bands designed specifically for correcting inwall problems. It was called the R/EQ-150 or something.
All of this aside, if you can possibly set up your office for box speakers, even if their placement is less than optimal, do it. If you go with inwalls, forget the high-zoot hardware- go midfi unless your long term plans include those electronics going elsewhere-the sonic gains of high end electronics are totally lost on inwalls IMHO.
Just my .02. Good luck. If you find a killer inwall, share it with us, please.
