Each week, our German correspondent slices and dices the latest rumblings, news, and quick-hit_driving impressions from the other side of the pond. His byline may say Jens Meiners, but we simply_call him . . . the Continental. At the Frankfurt auto show, two heavy, aggressively styled Audi concepts—the Nanuk Quattro_and the Sport Quattro—wowed observers, but [...]