Audiodany Nice system,
Hey it's cool to see someone else who owns a GRAAF GM-20! A friend of mine uses his modded GM-20 with Avantgarde Duos, it's an awesome amp with a lot more punch then you would expect from 20 watts. I would agree with you on Italian audio gear. He also has the Viva Linea preamp best pre I've ever heard. Viva Audio Devices is another amazing Italian company.
I'm sure you love your ProAc 2.5 but@86db,1 watt,1 meter they may a bit underdriven, if only in the bass.[I've even heard a modded GRAAF power the Maggie 3.6!]
If you ever get a chance to listen to a more a efficient speaker check out the BG Radia Z-92 www.bgcorp.com I own a pair and they sounded very dynamic with a couple of 11 watt Quad tube amps. At $2,500 new, I've seen them go for very cheap used on the Gon. The planar drivers and speakers are made Carson City Nevada with a lifetime warranty. [An awesome speaker that seemingly know one has ever heard of]
In general the more sensitive the speaker the better.
Try out a set of cryoed 6C33C's an amazing upgrade!
Have fun and keep listening.
Vinyl9