Personally I don’t think you’ll be able to tell the difference between the HD audio and the Spdif. I’ve tried to blind test it and I can’t tell. But, have fun!
Don’t spend too much money on it just to get HD audio working on that setup since it is kinda a stopgap measure. A new TV with HDMI will probably be needed sometime in the future and the $ would be better spent on a TV than on an obsolete soundcard.
