Factory service manual versus real expierence

I'm deciding whether or not to swap out the engine on my own. If I follow the FSM to the "T" it looks like a long process has anyone done this before? I had another tread and after reading the FSM I'm not sure if I could do it. The FSM is saying to remove trans, driveshaft, etc from the car. Couldn't I leave them in and just take out the engine and put in the new one?