Replacing door and frame

[stallard]

I am about to replace a hurricane damaged exterior access door and frame in a wood framed house. The new pre-hung door and frame is exactly the same as the one I am replacing. Should I remove the pre-hung door from the new frame before offering it into the opening, or should I install the whole thing as a unit, square it up and then remove the door to fix the frame?

[TexMex]

Normal practice is to have some temporary reinforcement fitted to the frame (such as a couple of diagonal braces across the corners and another one straight across the frame lower down). This holds the frame in shape while you fit it. You then remove the temporary supports, and fit the door.