A few days ago, BMW->ke178 tried to show us just how cool the M4 Coupe will be with the unveiling of the 4 Series Coupe M Performance Parts. Today, our spy photographers managed to catch the M4 Coupe->ke4183 out for a testing session at the Nϋrburgring->ke999 racetrack.

As expected, the M4 Coupe will look pretty much identical to its four-door sibling -- the new-generation M3 -- also expected to arrive by the end of the year. The spy shots revealed that both models will be equipped with a double-bubble carbon fiber roof.

Under the hood, the M4 and M3 will share the same engine: a 3.0-liter in-line six-cylinder engine with an output of roughly 415 horsepower. Initial rumors suggested that for the M4 model, BMW is developing an updated V-8 with an output of about 450 horsepower, but it looks like this will not not be the case.

Expect the new BMW M4 Coupe to arrive sometime at the end of 2013.

Click past the jump to read more about the BMW M4 Coupe.

Spy shots

The prototype->ke146 we have caught testing today is still heavily camouflaged, but we expect the M4 to look pretty much identical to its sedan brother -- the next generation M3 -- minus the two rear doors.

This means the two models will share the same aggressive exterior look, characterized by the usual M design elements: a larger air dam and lower bumper; a black kidney grille with an "M4" logo on it; more pronounced front-wheel arches; and larger air intakes.

For the rear, the M4 will get an aerodynamically optimized rear apron and the usual M sport exhaust system with quad tailpipes.