Flexijack out into coax in for DTS?

I would like a digital connection for music and movies. My X FI platinum card came with external IO drive so I have 3 options for making a digital connecton to my new logitech z-5500 speakers. Really only 2 because I have other optical dependant devices.
1. Optical out of IO drive.
2. coax out of IO drive
3. FlexiJack out of back of card into coax input of Z-5500

What about Flexijack? Will this sound as good and support DTS/DD? Is there a jack to fit flexjack out of card and into Z-5500 coax digital? I would prefer going out of my card instead of my IO drive if it sounds the same. In either case I will need a coaxial cabe. Will a more expensive coaxial cable sound better? Can someone recommend one, Thanks.