I do not know any of the specifics, but talk to laurion, he built our TV recording device and it's great. Amoung other things we don't have to pay TiVo fees and as metahacker pointed out we're not subject to downgrades. Also, though it hasn't happened yet, I've been promised that our computer-turned-TiVo will eventually be able to record two shows at the same time on different channels (using the same T.V.), have no idea how this will work, but it's useful.