S2 to S2 DT Migration

This might be a "Duh" question, but I am going to ask it anyway. I have a S2 Tivo that I upgraded with a 320 GB HD a few years ago, and after some initial hiccups (Thanks to everyone here for the help !!), it has worked flawlessly. Now, to the question.

I have just moved, and my new housemates are now starting to become accustomed to the Tivo, so my requirements from it are changing. I am thinking about taking advantage of a sale that Biglots is having on 80-Hour DT S2s, and I was wondering: Can I simply remove the HD from existing S2 Single Tuner Tivo, and place it in the new DT? It is the sole drive in my current Tivo, and would be the sole drive in the new DT. I have the original drive from the current tivo, but I do not plan to have more than one tivo active at a time. (If it matters, I am not a lifetime subscriber.) I would really like to keep the shows I have recorded, and not lose them in order to get DT functionality, so I am hoping that the underlying Tivo software notices whether there is another tuner or not, and activates functionality as needed, or requests a software update and fixes the issue.

So, am I just hopelessly dreaming, or have I clued in to something to make my life easier, like Tivo does?

Prototyper.