I'm not a big believer in expensive cables or speaker wire but I believe that there could be something to it. It's not likely that I will ever go head over heels and buy 10k speaker wire or 2k interconnects or whatever but I would think that it should sound better than 18 gauge zip cord and that the high priced IC's should sound better than the stuff you get at K-Mart.
Just how much better, I have no idea.
It seems that better conductors like silver should bring a better signal through and allow for better sound but it is possible that good old copper is just good enough. I have had IC's that had a hum to them when brand new, I suppose a bad connection or short somewhere but this made me avoid the no name el cheapo. I recently threw some old IC's out as they were just old, tarnished and I figured they needed replacing. I moved all the way up to Monster 300 series and could hear no difference. I did not really expect to and I realize that Monster is not high end nor is it expensive. It gets the job done and no shorts or hums so I'm happy.
Nearly 30 years ago, a friend dropped by and noticed that I was using 16 gauge zip for speaker wire. He told me about a small high end shop that sold something called cobra cable as speaker wire. He said that he was allowed to take a pair home for a demo with his Maggies and said that he could hear a definate improvement. I found it hard to believe but decided to try it for myself. I bought the stuff at nearly $3 per ft back in the mid 70's and this seemed quite high for the time. I too was certain that it made an improvement, somehow giving more clarity. Whether this was imagined or actually heard, I was pretty convinced.
At any rate, I now use 12 gauge speaker wire off the spool from a local high fi shop (now defunct) and it seems again to be good enough. I don't think I would use a smaller wire as I have concerns with too small not having the current carrying ability that it needs. Maybe Mike, Mtry or RGA could fill us in as to whether this is even necessary.
To me, once you have all of your components in place that you are satisfied with, maybe you can think about sturdying up your speakers with spikes or stands or possibly some other isolation concerns. If we all bought into all the tweaks, cable, wire and mods that are available we could stay broke for a long time without much satisfaction in actual results. When we buy something that is supposed to improve our system, we often might think that we did when in fact we did not. If it doesn't jump out at you as a considerable improvement, there might not be one at all.
Bill