Step 4 is a moral inventory, not a list of bad things you've done. The goal is to find out your pattern of behavior & fears. It is not a confession. Clarence Snyder, one of the first 40, has speaker tapes online and information on how to work the steps.
Going to any lengths? Sure. Making sure Step 3 is looked at, yes. Submitting? Not so certain.
My sponsor never read my 4th step. My sponsor shared some of theirs with me. Some things were not discussed as the pattern was quite clear. Prayer was very important. I felt profound relief during my 5th step.