2015 BMW M3 (BMW of North America)

BMW unveiled its 2015 M3 sedan and M4 coupe this week in advance of their official debut at the 2014 North American International Auto Show next month. The M3 and M4 are high-performance versions of the 3-Series and 4-Series, respectively.

We previously reported that the new M3 and M4 will both feature an all-new twin-turbocharged 3.0-liter inline six-cylinder engine that produces 425 horsepower and 406 pound-feet of torque. The engine is paired with either a six-speed manual or seven-speed dual clutch transmission. The previous 2013 M3 sedan and coupe are powered by a naturally-aspirated 4.0-liter V8 that produces 414 horsepower and 295 pound-feet of torque.

2015 BMW M4 (BMW of North America)

In addition to a new engine, the M3 and M4 feature various suspension and aerodynamic components to improve performance. The M3 and M4 feature rear spoilers that BMW says reduce lift and add styling to the rear end. BMW also explains that the exterior mirrors are designed to be aerodynamic and make a styling statement.

Autoweek writes that the front bumper looks "edgier" and is designed to better channel air into the engine. A power dome in the hood makes more room for the engine, the publication adds, and the fenders are widened and feature a vent that helps remove hot air from the engine compartment.

2015 BMW M4 Interior (BMW of North America)

Car and Driver is pleased with the overall appearance of the M3 and M4, saying they "look every bit as aggressive as their spec sheets indicate they will be."

Pricing details haven't yet been released, but the previous 2013 M3 started at $60,100. BMW says the M3 and M4 will go on sale in the summer of 2014.

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