Greetings!

Given that your garage the car, you should not have severe trouble or shorten the hard drive life that much.

But if you want to back up without a computer and are upgrading your drives anyway, the best recommendation I have is when you upgrade your empeg's drive(s), copy the files directly by using the empeg as the installation device similar to Step 7 of the drive upgrade FAQ and put your original drives in a safe place. I can send you more detail if you choose to do this.

Otherwise, I do not know of a direct disk connection method that will work well with the empeg. Perhaps a network attached disk, but you would still need something to do the connectivity...