The Pass amps are superb, and WILL mate nicely with the Proac 2.5's. The Plinius and Sim's are very good, if a hair behind the Pass's. Then the Classe Behind those.
I used to have Classe CA150, as well as Audio Research LS16 preamp driving some Thiel 2.3's. My system WAS similar to yours in a lot of ways. I upgraded amps to even a used Threshold T200, which was superb for cheap used ($1600). I used to sell the Pass, and Classe Stuf, andy my buddy owned the Plinius 250...I've heard the Sim.
It's all good gear, but I'd give the Pass a nod over the others, then probably the Sim, then the Plinius,then Classe.
Good Luck
Have fun
I used to have Classe CA150, as well as Audio Research LS16 preamp driving some Thiel 2.3's. My system WAS similar to yours in a lot of ways. I upgraded amps to even a used Threshold T200, which was superb for cheap used ($1600). I used to sell the Pass, and Classe Stuf, andy my buddy owned the Plinius 250...I've heard the Sim.
It's all good gear, but I'd give the Pass a nod over the others, then probably the Sim, then the Plinius,then Classe.
Good Luck
Have fun