All I can say is that the BG's are really growing on me with each successive listen, even more so than their big brothers, Wisdom M-75's, which I owned for 4 years, powered by Pass, Bryston, ARC and all Valhalla. I am blown away by how good these sound considering what is driving them, especially considering that Marty played his torture disc through a $300 Sony Blu-Ray. The only problem is that when I am watching TV or a Blu-Ray, I keep answering my phone or the door when it is actually on the soundtrack. Also, regularly I sit down to listen to a track or two and end up listening to 20!
Regarding SPL, I do not know their potential because I am running out of steam from the amp. Soon I will be adding a new Bryston 4B, which from what I have heard should really make a serious sonic improvement, because I hear my current amp's signature coming through in all playback. I will let you know about the SPL changes when I have the power to make them sing or break. BTW, they are 4 ohms so power will no longer be an issue.