My father owns the wood Quatro so I feel I can add some real experience to this thread, ANYONE AND EVERYONE who claims the Wood version is simply cosmetic is talking before hearing, yes the major improovement is coemetic and it is a beautiful speaker but it also has some trickle down benefits from the 5A wich are not in the standard version, you get between 5 and 10% improovement in sound over sock version. Is that worth it to you? I cant answer that but it sounds fantastic and is quite beautiful. Furthermore if you want insight on the Wood Quatro shoot Richard V. a call or one of his top-tier dealers, what Richard thought it was going to be to go wood vs what it actually took to achieve is an interesting story.
BTW my father drives them with Audio Research tube pre, and Classe Mono Blocked amps with near top of the line Audioquest cables.