A digital audio in a Quicksilver case yes. They are basicly the same case design on the inside, just different power supply to motherboard. You might want to change up the power-on board to be more compatable with your system. As for the MDD case, the answer to that is no. Since older G3 and G4 macs are ATX style design, the MDD was the first BTX style design. Reverse PCI slots from the cpu area.