Ok I would like to build a setup to use to backup my 4TB Ext drive and my 1TB iMac hard drive. The system can be very manual, I plan to back up everything about once a month. Right now I have only about 2TB of the Ext drive full and about half of my iMac full, so I would like something that I can easily add a HD too as I need more space. I am very willing to sacrifice looks and ease of use to save money on the setup. PS I wanted to say that the EXT HD is FireWire enclosure from OWC that I put two 2TB drives into. So I would like the backup solution to be FireWire as well.