Is there somewhere a listing of the different versions of tivo minis, and the hardware/functionality differences between them? I'm looking to shop for a few minis, and wouldn't mind knowing the differences between them (I commonly shop used equipment, it helps to know what I'm looking at). I have a 3 or 4 year old mini that I bought new. I don't know what version it is, but I know it is not VOX, but it is a RF remote. Probably the only key thing I need to know in the ones I'll be looking for is that I do not get one that is IR remote only. Everything else is probably not relevant to my usage.