I have a new MacBook Pro on order. I've read several people on the forum discuss taking the Superdrive out of the MBP, putting it in an external drive casing, and then putting a second hard drive in the MBP, in the empty space where the optical drive was. This sounds like a good idea for my uses. It's something I might be interested in doing. However, anybody's discussion of doing this always leads to someone else pointing out that this voids the warranty. Not good. Especially due to all of the issues I had with my 2006 MacBook Pro, which were taken care of under (the extended Apple Care) warranty, I would rather not void the warranty. If that was at stake, then I'd stick with 1 hard drive (or maybe an SSD, when the prices come down and the size goes up), and keep the Superdrive in place. But I suspected that "You'll void the warranty" was not the whole story. I couldn't imagine that changing a drive would void the warranty on the whole computer. I expected that the warranty policy voiding would be more specific to the part you tampered with. So, I called up Apple's Support number, and asked them, "If I take the Superdrive out of my MacBook Pro, and replace it with a second internal hard drive, will I void my warranty on the whole computer, or just the Superdrive?" The woman I spokewith unhesitatingly answered, "Just the Superdrive". Unfortunately, all I have is the spoken word of one Apple Support worker. I don't have this on record, and don't have it in writing. I could easily imagine that the reality of exercising this policy comes down to the knowledge or ignorance of the person whom you deal with, and perhaps her/his mood, too. Nonetheless: To the best I can tell, you can replace the Superdrive with a second hard drive or SSD, and only thereby void the warranty on your superdrive, not your whole computer. I imagine this also applies to other parts inside the computer that you might want to modify, too. Go ahead and mod your computers, with greater peace of mind about the warranty. I hope this helps.