The "most foolish" loudspeaker tweak/upgrade ... is


I suggest Von Schweikert Audio's "ULTRA Internal Wire Upgrade" at a 'mere' $39,700..

ptss
Suppose you could place an amp and speaker so that the terminals on the amp touched the terminals on the speaker. No wires at all. Would this not be the perfect setup? As good as it could get, no wire at all, and what some wire makers strive to achieve. I'm speaking in generalities here, no wire in particular, inside, outside, whichever. But it is impractical to place your amp and the speaker cone touching each other, so a length of wire is needed. Any change in sound that occurs once you've introduced a length of wire is strictly less than the no wire senerio. It cannot create anything new in the signal, it can only subtract. So, designing wires is strictly a subtractive process, what frequencies will be reduced more than the others? What effect will capacitance, inductance and resistance have on the sound? These are the properties of the wire that would not be there if things were perfect, And the amp was connected directly to the speaker with no wire. So, wire companies do research, and experiment with different metals and materials to see just what will happen. What subtraction will have the most pleasing sound. Remember, wires cannot make sound, they cannot add anything to the presentation. Only subtract. The materials that wires are made from are not inherently expensive, so the bulk of the money spent on them is to pay the researchers for their time, and intellect. Whether you think the price asked is worth their time and intellect is completely subjective. To each his own. 
ptss
30K for wire. They should quite using chip board  boxes, that might be worth a few $$$
FWIW, I dont really care how mucfh a person spends on speaker wire, which seems to be the  most answers, to the OP's question, so I'll give my humble opinion. I would totally forgo any cable upgrade until my ROOM was at its absolute best configuration, I.E treated for sound. Thats also a very inexpensive fix to improve on any, and I mean any speakers performance in a given room. After that I would obtain the least expensive, reputable cable i could afford and I will venture to say that a relatively reasonable priced cable will really satisfy. Of course if you have unlimited resourches go for it.
Alpha gt - You have put into words the most logical explanation of wires i have ever seen on a forum . "Ideal would be no wires between components and no wire can add something that is not there to begin with"    Perfect statements !
Alpha gt,  IMHO you are correct.  'To each his own':  I would only add that, as members of the human race with our foibles and our sense of humour, we will make fun of silliness whenever we can.  For my own part if I ever bought such cables I would expect to be laughed at.