I am thinking of getting either a 4-tuner Roamio basic or a Roamio Plus. From my understanding while reading some posts here, I think I saw something that says the Roamio Basic is user-upgradeable. Can basically be easily upgraded by the user by simply replacing the drive yourself and just dropping a fresh new hard drive into the unit. The Roamio basic then does everything needed to properly prepare the drive for full use. Essentially a plug-n-play type procedure. Is this correct and how it works? If so, I am assuming upgrading or repairing a Roamio Plus/Pro would be a little more involved, correct?