On the ADV site there is a link(many links) to all things Dakar.
There is a thread that tells of scrutneering and how they lock the engines so they can't be swapped MORE THAN TWICE!!!
That's right, they can swap the bottom-end twice but the top-end can be changed every night if they want and probably even at lunch if they have parts with them!!
So much for it being a rally.
I vote for the guy on the Bully. probably has Donny Newell on his crew complete with a heap of nos pistons