Amp Size/Recommendation to Fill a Large Volume Room

HI All,

I have begun building my dream system and need some advice. My B&W 802D3's are powered by a Naim Uniti Star (for budget, this was the best component which gives me much capability in an all-in-one package.) I am searching for an upgrade of amplification (to start, I would use the Naim as a preamp.)

I have a very large volume room (14x18ft. with 16 ft ceiling - very open concept great room). Needless to say, my current Naim is not filling this space. What size amp (wattage or high current delivery) should I be considering. As an aside, I like a warm presentation and nice bass. Also, my ears tend to gravitate towards class A amplification. More recently, I was able to compare the Luxman integrateds (not in my home) and loved the class A presentation.

I have been researching like crazy (Pass, Luxman, Mcintosh, etc..) but still confused as to what direction. I am intrigued by the Pass XA 160.8, but wonder if it has enough juice? Would the X260.8 be a better fit? Also, I found the Luxman integrated to sound nice. Never heard the M900u though. I do not listen to music all that loud, thus, I do not require rock concert levels of volume. Am I on the right track with with the aforementioned brands/models??

Please help!!

Be safe!