I just got my 40 hour TiVo and I can already tell that I am going to want to upgrade. I am disabled so I watch alot of TV. I record most thing in basic or medium quality but I still want more room. Which is the best way to go for upgrading? (Money is minimal) Should I upgrade the system I have? (I've read about upgrading) or get another tivo? If I do get another tivo, do I have to purchase the monthly service again? Should I try referring my friends?