I had a Sony S1 lifetime and last July, 2006, I added a S2DT to my account. I got the $6.95/mo MSD plan. The MSD rate was in place before Tivo changed their pricing in the fall of 2006 and was grandfathered. This year I traded the S1 in for the lifetime offer of a new S2DT. So right now I have a lifetime S2DT and a grandfathered S2DT at the $6.95 rate and no contract commitment. I have been toying with the idea of replacing the grandfathered S2DT with an HDTivo. If I buy the HDTivo can I just go into my account and change the TSN of the $6.95 Tivo to the HDTivo's TSN and still get the the same rate? If so, does it still get treated as grandfathered without and contractual period?