Electrocompaniet AW-180 for Avalon Opus Ceramique

I’m using an Electrocompaniet EC-4.8 Pre-amp and AW-180 Mono-block power amp for my Avalon Ascendant II speaker, my power-amp can drive Ascendant II fairly easy, the sound is beautiful and I’m totally satisfy of the result.  Recently I’ve trade-in my Ascendant II to a pair of very good condition, beautiful Walnut Cluster Burl Opus Ceramique. And I will receive this new speaker a few days later (very excited!!).   Now I’m worry if my AW-180 cannot handle Opus Ceramique very well, should I upgrade my AW-180 to AW—400? Or if I change my amp to AW-400, do you think the sound quality has big improvement?  Of-course if the improvment is very small, I won't consider it.

Here is AW-180 and AW-400 sales specification:

http://www.electrocompaniet.no/products/classic/poweramp/AW180.html

http://www.electrocompaniet.no/products/classic/poweramp/AW400.html

PS: My listening area is very small, about 11’ x 20’, that’s why I prefer Opus Ceramique instead of Opus I (Two Eton woofers)