Boy, I would say good luck! Those speakers are the most amp sensitive I have ever heard. They sounded plain awful with an Audio Note Oto SE, and acceptable with a Graaf OTL. I have also heard the Duo's with the Cary CAD-805AE SET, which was a combo which worked very well. Magical top end with a full midrange.
It seems that despite the claims of high sensitivity, the Avantgardes benefit from a bit of power.
Just my limited experience from auditioning the Avantgardes. I was going to buy them, but chose something else instead.