Here's the thing with ultra-expensive cables. It's like going to a super fancy restaurant and ordering a £100 pasta dish which makes great claims about it being the best pasta ever... but it's pasta which was bought from Tescos for £1.50.
That is not the same as eating £1.50 Tesco pasta, vs. paying decent money to eat somewhere that makes their own fresh pasta.
Virtually all cable companies have no production facilities and no R&D because they own no test equipment. They're just buying bulk materials for peanuts, wacking them together and selling them for markups so vast I struggle to think of another product line which does the same thing. If you look at someone like Blue Jeans Cables, there's no smoke and mirrors - they disclose exactly what their cables are made from and make no silly claims and their pricing is fair. Then you look at say, Virtual Dynamics... a few people started cutting open their cables, some accidentally, and discovered that, despite the usual pseudo-scientific jargon about it's properties, it was nothing more than bog standard wire, some sandblasting pellets, stuffed inside garden hose to make it thicker. Their power cables weren't even officially approved as far as safety certs went, so if it were the cause of a house fire your insurance company would laugh at you. Definitely not the exception to the rule, either.
Ultra expensive cable companies rely on the fact that nobody is going to ruin their cables pulling them apart to see what's actually inside them. By contrast, with an amp or DAC, you can always remove the casing and see the quality of soldering, the chips and op-amps used, and so on.
Ultra expensive cables are EXACTLY in the same boat as:
http://www.lessloss.com/blackbody-p-200.html
All of this
http://www.machinadynamica.com/machina5.htm - people DO buy his stuff and I'm 99% sure he's the greatest audio troll ever
All of this
http://www.shakti-innovations.com/audiovideo.htm
Etc etc. Note they all have 'white papers' too, saying a lot about nothing, really.
Energy bracelets, healing crystals and all that stuff... similar isn't it?
Again, not saying cables can't sound different (presuming extreme variations the properties which effect the signal), but there's high quality wire w/nice braiding that costs a fair bit, then there's "you are a mug if you buy this".