Spider appears to be in great shape. Glue was intact 360 degrees, spider was perfectly flat, nothing appeared out of the ordinary. The behavior is the same on both speakers, and it tapers off from the lowest woofer up to about the 3rd from the bottom. After that, the other 5 are really tight.
I assigned a 40Hz crossover on the fronts with my processor, and off loaded the low freq to my subwoofers, and the dramatic excursion went away (not surprising). Of course, so did the tight low end that the LS6 can deliver.
I think it's just that the lower drivers have more volume behind them with the large chamber at the bottom of the LS6, so they can get more movement when driven to extremes like this. Keep in mind, this was 97+db at 10 feet away, so who knows how loud at 1 foot. Very, very loud, with no audible distortion. I spoke with Danny, and we agree that performance is pretty incredible.
The song was: The Maroons - Beautiful You
BTW, it wasn't until I completed the LS6s that I understood the comment, "These don't need subs". I've heard others mention that about their speakers, and it never made sense, because my full range Polks definitely needed subs. The statement makes more sense now. I still like my subs, but now they are optional.