Just rest a little easy. As nervous as these Xfires sometimes seem to be, they are, for the most part, extremely reliable. Just not common. A good thing right?
The up side is that you own a rare, quasi EXOTIC that can be worked on and kept running by more than the factory guys,,, like in the case of say owning a Lotus.

Everything about the car is Mercedes except the paperwork. Anybody that says it is 50% Chrysler or 95% Benz doesn't know jack about them.. Walk away and find someone who does know.

A Mercedes stealership might know. But, few will even touch it. Find an independent who specializes in the Diamler line,,,,you will be OK.