You might want to read this:
http://www.roger-russell.com/wire/wire.htm
The long and the short of it is this:
ABSOLUTELY NO ONE has EVER demonstrated an ability to tell the difference between special wires and ordinary wires of comparable gauge with normal lengths. Excluded from that are "wires" that add circuits that degrade the sound.
Many people have claimed such ability, but when properly tested, they invariably fail. Believing people who claim to be able to do something that no human being has ever been able to demonstrate the ability to do is like believing someone who says that he can run faster than a speeding bullet or leap over tall buildings. Somehow, though, when an audiophile claims to be able to hear a gnat's wing at a mile away, many suckers are ready to believe them.
Once a wire is good enough to make no audible alteration to the sound, any "better" is pointless.
I personally use
some very revealing speakers. I use ordinary speaker wire and interconnects, and a CD changer with them. The difference between a poorly recorded CD and a well recorded CD is dramatic. But there is no need for magic wires or other such nonsense.
You have put your money in speakers that are supposed to be good, and that is where you should put the majority of your money, if what you want is good sound. You then need amplification adequate to drive them (in your case, that need not be expensive), and a decent source (in the case of digital sources, they need not be expensive).
The manufacturer of your speaker seems remarkably sensible regarding these matters:
http://www.harbeth.co.uk/uk/index.php?section=products&page=faq#8
http://www.harbeth.co.uk/uk/index.php?section=products&page=faq#5
Most manufacturers are afraid to say such things, in order not to offend the crazy audiophools. Frankly, taking a look at this has gotten me to respect them very much, even though I do not recall ever having seen any of their speakers, much less heard them. (I have, however, heard
of them.)