I really wonder. Do you actually listen or just read spec sheets? Mac uses crummy DACs just like every Computer. I use a FireWire connection from my Mac to a FireWire DAC and believe me, the improvement over the native computer DAC is not subtleYou can't improve the Mac's performance audibly. They are already audibly transparent with specs far beyond human hearing. You might improve theoretical sound, but only bats and dogs would appreciate it. Macs contain DACs that perform just as well as audiophile DACs. They've been specifically designed for music and video production and playback since the old Powermac days.