Congrats on this beautiful setup, i also own a Diablo 300 and drive a pair of Thiel CS 3.7s.
The Diablo's rich sound is a great match for my Thiel speakers.
And if you can afford the A5s I reckon it will be a perfect combo. A mate has has the Diablo 300 and Sonus Faber Il Cremonese. Wonderful system. But I can’t help but think that the transparency and neutrality of Magico works better with Gryphon amps.