Hi I would like to point out that you have another option.
First the best software for copying your hard drives bar none is Norton Ghost.

Now even with Top shelf software you are looking at extended times for copying in the 7-8 hour range each, for both drives.

Though relatively new here I am a computer repair technician. I have hardware that will copy your hard drives in 45 mins or less for each drive.
I do computer repair from my house and stand behind whatever I do.
I don't necessarly advertise on other folks forums. But I can tell you that I offer one day service. Where I am located I cater primarily to the seniors community and other folks who just don't have the money to repair their ailing computers. Computer shops where I am located charge $75 a drive when they copy using software. My hardware makes EXACT copies of your data with out using a computer. I charge less then half of the $150 you would be charged to save your drives information.

I have enabled email from members please fell free to contact me if you think you might want to engage my services. I am also avalible for phone calls. I'm always at home as well. I am a Retired/Disabled former Los Angeles county Paramedic. So I find myself with plenty of free time on my hands.
I am currently working on a comprehensive user guide with many of Tivoupgrades answers for Tivo troubleshooting in PDF form. This will mean no more searching through the many posts here looking for answers.

I hope you are able to clear up your problem and I hope you aren't offended by my chiming in here. I know how frustrating computers can be. Whatever path you take to copy the drives. Especially if they are noisy, then the bearing is probably going out. If you can get a stehascope you can pull the top cover off your Tivo and listen if you hear a knocking or a clank you know you have found the drive/drives going bad. Keep them powered down or you risk losing a big chunk of data. Prices for rebuilding hard drives that have broken starts around $750 and goes higher if it's done in a clean room facility.

Regards, Howie