Changing it all out at once is easier said than done.
The amount of work is large but doable and the cost is not cheap. I spent $1200 on parts alone and it took a week of working on it after work. Been there, done that, wrote the book, sold the story, got the shirt!
Here is a kit with everything for $788. This is a good place to get parts from. Bob is very knowledgeable about the powerstroke.
Powerstrokeshop.com