Well my GF’s G3 originally came with a DVD drive, but she wanted to burn CDs and watch DVDs on it. So I practiced on my server, here are the results. It works fairly well, except for the RAM rubbing on the top of the top drive. I had to put the longer DVD drive on top because it wouldn’t sit flat due to the cables coming from the power supply, but even with the shorter drive on the bottom, it pushes up slightly. To get it all to work, I used a flathead screwdriver to pop the zip part of the drive caddy off, then dremeled the remaining protruding parts off. Then I took the dremel to the metal part of the case itself, removing the area previously used to screw the caddy into the case. Then all the sticking-up parts within the case were bent down so that the drive would sit flat, and the cables were moved to sit below the metal shelf. The Zip section of the blue bezel popped right off. Initially, I wanted to get a second CD bezel and put it on there, but because of how the spring is routed and because of the size of the CD section, it just wouldn’t work. Initially, the metal section under the bottom drive that I had to bend down ended up sticking right between the fins of the heatsink, and the computer would often just shut off when I closed the case, so I bent it way down, so it no longer is a problem It works great, and OS X recognizes discs in both drives at once!