Need help

Just got off the phone with Tivo. You know they have the basic Roamio on sale for 149 with 249 life time. Wanted to get the new over the refurb because I have never had a new Tivo always bought used. But then they said if I wanted a plus or pro I could get lifetime for 99 since I am a long time customer. I was going to upgrade the basic with a 3tb drive lets say for 120. So I can get the basic and upgrade the drive for around 520 or get the plus for 500 but that only has the 1tb drive. I don't think I would use the streaming much or at all on the plus. I would be getting the 6 tuners instead of 4. I have a series 4 with a 2tb and it is 75% full. It is on it's last legs. What should I do, what should I do?

**Sorry I was in such a rush I forgot to finish the title of the thread. I do need help, more ways than one.