Apparently it was $2500 for the pair.

Ahh, the world of esoteric inexplicable high-end audio.

To keep audio noise down, you don't need expensive cables. You just need shorter cables. Likewise, audio frequencies are so low that cable quality is largely irrelevant, but video frequencies are another matter entirely. Particularly for longer cable runs, you might see a visible improvement for using higher quality cabling.

In my system, I'm running "Radio Shack Gold" cables. They have nice gold-plated connectors, I'm told they "test well" (whatever that means), and they're cheap. For my speakers, I'm running Home Depot 12ga wire. It's oodles cheaper than audiophile wire, and it will handle more than enough power. I crimped the cables with generic U-shaped connectors, also from Home Depot. Works fine, costs peanuts. I've heard some people use electrical "zip" wire (normally intended for running the 120V A/C to outlets). That will also sound fine, but it tends to be solid core, making it somewhat inflexible, which can be a problem if space is tight behind your amp.

The two biggest things that effect audio quality are the speakers and the room they're in. Moving the speakers around physically can have a massive difference in quality, and all it costs you is the time to move them around and listen to the effects. Having a good amp does make a difference, particularly at higher volumes, but unless you're buying seriously esoteric speakers, yee olde Japanese receiver has all the power you'll ever need.

(Side note: if you're serious about making things sound good, another important issue is your noise floor. You'll have a possibly loud fan in your video projector. You've got your air conditioning. You may have a hardwood floor or glass windows that make the room more "live". Adding rugs, window coverings, and other such things can make a big difference.)