Again, I'm no expert audiophile, but extra power is not just about loudness. I don't listen to anything exceptionally loud. From my experience which is admitedly limited, and based on my ears and not scientific data, the extra power brings more "depth" and substance and greater detail. A lot of "junk" (both amps and speakers) will play loud.
I remember being a freshman in college when a friend purchased a system with two seperate 250 watt Crown amps., a Crown pre-amp, a pair of KEF speakers and a Dual turntable (remember vinyl) from a high end audio store. We set everything up in his 10' x 10' bedroom in the house trailer he lived in, and listened to "Silk Degrees" by Boz Scaggs (boy am I dating myself with this post) in plain old stereo. It sounded absolutely awesome, and it wasn't about loudness. It was about detail and musicality. Something that scientific data may not always be able to measure.
Like I said, I'm no expert or technician, but I think I have a pretty good ear. To my ears, and maybe it's just psychological although I tend to keep a pretty good perspective on things, the M80's with the 7500 sounded more refined than with the 7125, not necessarily louder. If it was just about loudness, they'll play plenty loud with my 85 WPC Yamaha.
Anyway, just some thoughts.
Regards.
