BMW M3 and M4 on-track at Road America (pictures)

This year, the M3 and M4 are split, with the M4 being the two-door, and the M3 the three-door.

A BMW M4 on track at Road America in Elkhart Lake, Wisconsin, sporting a GoPro on the roof.

The change in names, from M3 to M4, brings the car more in-line with BMW's other series.

Lines are mostly the same, but the rear fenders are quite a bit different on the two cars. The coupe a bit more subtle, the sedan having more pronounced fender flares.

BMW was kind enough to line up a selection of both to test out.

Carbon fiber roof? Yes, standard on both cars.

Big, composite brakes are an option. They proved very capable in the hard braking zones at Road America.

The interior is a good mix of comfort, sportiness, and technology.

A selection of colors is available. White may not be the most stain-friendly, but it sure looks clean when new.

BMW's familiar iDrive interface is here, connecting a large LCD on the dash.

Yes, of course the seats say M3.

Carbon fiber highlights an option in the interior.

A new, turbocharged V-6 engine has minimal turbo lag, and dig that carbon fiber strut support.