I am driving the Amatis by Goldmund 29 and is quite okay in terms of power requirement in my listening room of 11 ft x 8 ft. My impression is Amatis are never too colorated and I am satisified with its bass performance (of course very terrible right out of box but much better after 2 months).
My amatis are only 3-4 months old and I have tried different preamp with it since then. I found their mid-high is very transparent, and some people may find it on the thin side. Preamp tried are Audionote M6, Nagra PLP and Conrad JOhnson 16LS. I found that with Nagra the sound is too clean, too analytical, while for M6 the sound is too forward, too solid, and too rush (I mean M6 is not very good at analysing the music between the notes) however sound sweet and better texture. For the 16LS, it is the most average preamp among them which gives a bit of warm but yet transparent soundstage, and best dyanmics contrast.
From your system, I really envy your ART and I would suggest you to try out Goldmund 29.4 or millenium ($$!).
For the front source, I would avoid equpment with too neutral or noncolorated in characters. I little bit taste or musicality would make the speakers sound better. For the cables, I tried some silver cables such ANVZ, Siltech, etc and found them a little bit on the bright side and make the Amatis sound thin. I am now using ANVZ, XLO LImited edition and some Mogami interconnects.