sonus faber strad power amp suggestions


I am powering sonus faber strads and martin logan summits and anML center channel through a krellkav500 and akrell
foundation preamp I should put the strads thru a separate 2channel amp ,suggestions bryston4b3 or passlabsxa350.8?
drmarshotel
the "strads" are obviously stradivai ,i am a "speaker guy" and have spent 50 years to reach this level of speaker system. That said, my orientation is "power is power".I am very naive with respect to amplification. my room is roughly 25 by 35 and my set up "sounds great", but i seem to be selling my speakers short with the KAV unit. so any feedback on power amplification would be very helpful!
I am using Pass X260.8 amps with my Strads and really enjoy the combination.  They have more than enough power to fully load my 17 X 34 X 9 room.  They stay in Class A up to 34 wpc, which means that I'm listening in Class A most of the time.  The amps are detailed, dynamic, and on the warmish side.  I use a Pass Labs X22 preamp and X17 phono.  In my experience, whenever I use electronics from the same manufacturer there is a special synergy.   While there are many good options, Pass Labs is hard to beat for the money. 
i could spend on the high side of $5000 for the right piece,I imagine a 5-channel preamp upgrade would be additional. I am leaning toward Pass Labs ,is 150.8 enough...or 350.8? I listen mainly to dvd-a and blu-ray formats(steve wilson prog rock remixes, highly detailed stuff). so $10k+ for the two pieces should be doable