upgrade from single tuner to dual tuner

[me10lee83]

I have a single tuner 40 hour series 2 tivo and I am looking into upgrading to a dual tuner. Is this a hardware or software thing and what exactly do I need to buy to do this?

[Lou Jacob]

I have a single tuner 40 hour series 2 tivo and I am looking into upgrading to a dual tuner. Is this a hardware or software thing and what exactly do I need to buy to do this?

These are two completely different types of units. TiVo makes a dual-tuner unit which can be purchased from them directly (https://www3.tivo.com/store/boxes.do).