I am thinking about buy a used MacPro from mac of all trades, Apple Mac Pro Intel Xeon/2x 2.66GHz Dual-Core (4 cores) 4.0/320GB SuperDrive-DL (7300 GT 256MB) . Leopard comes installed, and the OS disk are not included. I want to upgrade the HD to 1Tb. But since there are not disk included, here is what i think are my options. 1. back up the computer using time machine, change hard drive, then migrate from time machine drive. 2. buy new hard drive and then install snow leopard (i would buy the $129 Sl, iworks, ilife dvd). Am I correct that both options will work?