I have read a number of post re: cloning. I just purchased a wd black caviar 640 to replace a working 160 seagate. These are both 3.5" SATA internal drives. I have installed but not initialized the wd yet. After reading some posts, it appears that if I clone the seagate to the wd, the source disk (seagate) will no longer be bootable. I'm not sure if that is due to changes on the MBR, etc. I need the seagate to remain bootable. If I did a restore from an external hard drive image to the new wd, will that limit the size of the drive to the original? I want to format the new 640 as one partition, clone the drive, and retain the extra free space for future use. Thanks for any insights.