I'm pretty sure the general public understand the costs of owning any German car. It's the first thing that usually comes up when you talk about these cars.
Never bought an extended warranty plan, but so far, count me as one of the lucky owners. Only thing that has happened was the water pump/thermostat but (which will die) and had an indy that I trust and know do it for the cost of the parts. Spark plugs, oil change, brakes all done myself.