Dynaudio c4 signature & c4 platinum difference

From what i read, the crossover is different.
Dynaudio used a different crossover on the C4 signatures then the regular C4 speakers.
Also the speaker cabinet on the C4 signatures are in a gloss color.
I haven't heard the new Signature C4's, but i did hear the regular C4 speakers at the 2002 Stereophile show.
The C4's sounded really good. The midrange was very open and the bass was tight and upbeat.
Here's a video of the Signature C4's in the Gloss color.
The cabinet definitley looks better then the regular C4 speakers in the gloss color.
https://www.youtube.com/watch?v=8nerDM1IzTg

10-08-15: Doug99
From what i read, the crossover is different.

Actually the crossover - internal wiring and a new doping on the tweeters was the MKII/Signature changes (and the finish). With the Platinum they only changed the baffle to all black and jacked up the price. So the MKII/Signature/Platinum all sound the same but better than the originals. The difference is the original needed to be turned way up to sound the best whereas the newer ones sounded better at lower listening levels.

That said the originals did play a bit louder when cranked to the Max.

identical except for esthetics.. I went with the Signatures myself. Beautiful speakers.

Identical except for esthetics. I went with the Signatures and used the savings on something else. I love the C4S'

Please forgive me in advance about the Dyne Audio C speakers. What role does the large almost slab looking pillar open to the drivers back action? It looks like the drivers are put the baffle which is then attached to the big structure, but open and communicating with the pillar? I am sure it was designed to look like that but isn't.
Can some one explain how the speaker works, e.g. the tweeters do not communicate with the large structure, etc.