Was wondering if I can just open the oil pan pull the pistons and replace the rings on my blow by demon. First step to fight the blow by.

Has anyone done this or have any advice. What reasons can i not do this?
Called a reputable MB mechanic and said that I need to pull the motor -cost if he did it, between 5-8k. I wouldn't mind spending a week in the garage for it. Everything besides the oil consumption is great on this 220k beauty.