Best Interface for Apple G5 Computer to DAC

[cbman]

I am just wanting to get my feet wet in setting up a music server. To start out I just purchased a Apple G5 Computer (as recommend by the site). I currently have a Lite DAC with a optical and coaxial interface. I have 3 questions:

 

(1) To get the best sound should I use the optical out or FireWire out on the Apple G5?

 

(2) If the recommendation is to go with the fireWire output, what would be the best recommendation for a interface to go from the FireWire to SPDIF? If possible I would like to get an interface for $300 or less (would be willing to find something used on ebay or Audiogon)

 

(3) Is the new Mac Mini that much better than the Apple G5 in establishing a music server.

 

Thanks for your help as I am trying to learn about creating a music server.