There's something to be said for persistence, especially in the face of rejection, but in the case of the Mercedes-Benz R-Class, persistence may not be enough. The slow-selling crossover has hit its zenith, but is still short of the hopes Mercedes had for it when it debuted in 2005. Built in the U.S. at the company's Vance, Alabama plant, the R-Class has continually come up short of its goals. But Mercedes doesn't seem bothered with the poor performance, reports Automotive News. "We have reached the level we can sell it.