My speaker is 6ohm 87dB, and on my MB3, the volume control always stays at past 10 o’clock. Most of times I set it to between 11 and 1 o’clock. So the high gain is not a problem for me.
I wonder whether C2500 would be a lateral move regarding the sound quality. I don’t miss a remote yet, so I will stay with M3B for a while. ;-)
Anyway, I like the sound of M3B a lot. It beats my Plinius M16 preamp easily. I use M16 in another setup for casual listening, and I also ordered a spare tubes for M3B from AI, so I hope I should be good for many more years to come.