I had MIT Shotgun cables for many years. I replaced them a few years ago with Nordost cables, and the change was dramatic. Audio stores and manufacturers usually hook their components up with Nordost cables to show off the benefits of their components.
@jafox is correct, you need to buy cables that make a difference. For Nordost, Heimdall is the tipping point where everything at that level and above makes a big difference. Cables are as important as components. Look for used cables, they have a nice discount. I've upgraded most of cables to Nordost Valhalla or Odin, but I got them used. I went to an audio store a couple days ago to listen to Sonus Faber Olympica Nova V speakers, and they had them hooked up with Nordost Valhalla cables.

