Are you saying that if the drive is removed from the case they can't connect to sata as an internal drive? ? ?
Yes, that's what I'm saying. They have the USB connections soldered onto the HD instead of the typical SATA interface, which is what you would need to make it into a laptop hard drive (2.5" drive).
If you want to rip apart an external drive, I recommend sticking with Seagates, Toshibas, or most Hitachis.
However, Hitachi was bought out by Western Digital, so they might start doing the same thing soon.