2015 BMW M3 sedan and M4 coupe -- 2014 Detroit Auto Show

When the redesigned 2015 BMW M3 sedan and M4 coupe go on sale in the summer they'll face stiff competition — but so will competitors. Cars.com reviewer Kelsey Mays got an up-close look at the two versions of the luxury sports car as it debuted this week at the 2014 North American International Auto Show in Detroit, noting improvement in nearly every category.
Perhaps the most notable change is swapping the previous version's eight-cylinder engine in favor of a turbocharged six-cylinder. In the process, substantial improvements were made in horsepower, torque, sprint time and fuel economy. Watch the video above for more.