BMW is preparing its new M4 for a debut at the 2014 North American International Auto Show, and the final testing stages have apparently involved many, many laps of the Nürburgring. The only problem is, the two-door track star appears to have a case of the waggly tail, as spotted by a spy videographer. Generally, the serious nature of testing limits these sorts of shenanigans, but don't tell the test driver that. Besides some tail-happy fun, this video is one of our first indicators of what the M4 will end up sounding like.
Autoblog , BMW M4 prototype powerslides around the 'Ring, BMW M4 prototype powerslides around the 'Ring
