ASAIK, the BBE is an equaliser with delay function. SO, in yr present set-up, the BBE is probably improving the in room response, at the expense of some distortion. Obviously, the pros outweigh the cons!
I like your speakers!
Is my perceived success with this item due to the fact that I'm under-powering my ohms with my low powered mono's,Other than that yr amps have at least ONE kt88 (~35-40W)/ channel, I know nothing about them -- so I can't say!
I like your speakers!