About cable burn-in, this from Nordost:
"During the manufacturing process, as insulation is extruded over the conductors, gases can become trapped. This combined with the high electrical charges often found in new cables, result in a brittle and bright sound that lacks the detail and depth desired for music reproduction. There are a few ways to solve this problem. One way to burn-in your cables is to simply hook them up in your home audio system and play music for a minimum of 100 hours. Even better, use a burn in disc, like Nordost’s System Set-Up & Tuning Disc,, which provides a track specifically designed to produces a range of tones that stress the cables and expedite the burn-in process. However, the best solution is to treat your cables using a designated cable burn-in device such as Nordost’s Vidar. "
Personally, I think this is utter crap, to sell Vidar burn-in services, or setup disc, to the gullible.