Failed lifter, see original post. While it may have only damaged the head and one cam, many manufacturers won't have the dealerships open an engine or transmission. Notice with this one they even had to send it back to NJ for a manifold swap.....the entire forum just went quiet while we wait for that answer.....
Re: MNA, I have to agree, I've never dealt with a company that has such a lethargic customer support ethic despite the best efforts of their dealers. To be honest I'm surprised they covered the rental car beyond 5 days, which is their policy.
However, I will say that an engine failure like this is unusual, I was talking to my service manager the other week and he was commenting how trouble free these engines have been.
BMW has been a completely different experience for me, as a customer. Issues dealt with promptly, no attempt to pass the issues off as not covered, and all I've had to buy are tires and fuel.
What year is your vehicle?