I used to ask for the parts that had been replaced from one van dealer we used to deal with and also a Merc dealers when I discovered the workshop staff were doing private jobs, all they were doing was taking off parts in the dealership cleaning them and using the new parts on the pjs.
Of late mine has gone back to the factory for servicing, personally I don't think the dealer have the electronic know all to deal with some of the aero issues.
Car dealers don't you love them.
