Hi Chuck,
I know you mentioned INT30A bottomed out on your 1007Be. If you're looking at Diablo, would it be possible to wait until after the speaker upgrade to try out the amps, particularly XA30.5? Many people commented XA30.5 is sweetest sounding of XA.5 series if the speakers are efficient enough (I wouldn't know because I only have experience with XA30.5). Your experience on INT30A maybe due to its not being as "powerful" as or relatively lack of control compared to XA30.5. I understand INT30A amp section is the same but a combo like XA30.5 + XP-10 or XP-20 should be much better than amp + volume control (sharing power supply, capacitor size, etc).
I'm saying this because I had 1008Be and now 1028Be with the same XA30.5 and even at very loud level, the amp stays in class A. My room is 18x25. Besides, I do not think XA30.5 + XP-10 would give up anything Diablo has to offer if source and cabling are up to the task. More importantly, it's much less money and boxes/cables than XA100.5 + XP-20. If the speakers are Scala though, I wouldn't want anything less. BTW, Focal announced there might be a Scala II (I was also told it is not possible due to important changes to the cabinet).
But of course I don't doubt XA100.5 monos will outperform XA30.5 stereo in any way.