PrimaLuna Premium Dialogue integrated amp with B&W CM9 speakers

I currently own a pair of Bowers and Wilkins CM9, first generation speakers. I've been easily driving them with a McIntosh MA-6850 150 WPC solid state amp. I'm thinking about selling or trading the McIntosh in for a PrimaLuna Dialogue integrated amp, either the Premium or the Premium HP. I really don't need the headphone section in HP; I have a Woo WA6-SE dedicated headphone amp. From the specs it appears that the only other difference between the Premium HP and the Premium is power, of which the HP has double, in both Ultra Linear and Triode modes. The listening room is approximately 20x15 feet. My other objective is to make the B&W speakers sound a little less bright and more musical. I think that listening in Triode mode would accomplish this. My gut feeling is that the 20 watts of Triode power in the Premium amp will not be create enough headroom in the CM9s; I listen to music at moderate to loud voulume levels. I do not have a subwoofer. Any opinions or comments in regard to this will be appreciated.