Once the automotive equivalent to ordering low-fat vanilla yogurt when surrounded by exotic Italian gelato, sedans are no longer considered cars of compromise—a sensible conveyance for the slippery slope of increasing responsibility. Instead, many of today’s top family-friendly models would be equally at ease on the track, and they have the looks to boot. Whether it is a 640 hp coupe, a limo limited to 195 mph, or a million-dollar masterpiece, the following four-door cars were among the most popular we presented in 2015. —…