I have the 40th anniversary models with the carbon fiber side panels and woofers, beryllium tweeters and some woofer mods and also a very thick inert ported rear panel. They only have 1 cap to crossover the tweeter, which extends out to 40Khz. I think it's now a high quality Mundorf cap.
They produce ample bass flat down to 40HZ with extended highs, very detailed light and airy. they overall have a very natural sound to them. I highly recommend them especially if you're pressed for space or tired of moving large heavy floor standing speakers around.
I've heard that they require a very long break-in period in which they keep improving and smoothing out over time, so let them play!