Here's a video to answer some of your questions regarding the E55's engine rebuild. I mentioned the cost of the rebuild, list of required parts and going over some of the necessary tools you'll need along the way
Here's a link to the parts list:
https://docs.google.com/spreadsheets/d/1horUaRQGnL82lORd82Fv06O-CTSfY3_sJewN4HAWWCM/edit?usp=sharing