I'm sorry to hear that you're recordings aren't playing back very well. I'd like to help check this out for you.
I have taken a look at the box remotely and all looks great signal wise. The hard drive status doesn't give me all the stats right now so I'm unable to see if there are any errors at the moment.
Can you please let me know if you've had any picture issues on the Live channels? Or is the picture problems exclusive to the recordings?
Just to let you know in advance, if a TiVo® box is replaced for any reason then sadly the recordings will be lost. But as dannylau mentioned data can be imported to the new box. Data relating to Series Links, Wish Lists and Thumbs Ratings. All the details can be found here: