The latest spy shots of the new BMW M4, which is seen here performing high-speed testing at the Nürburgring ahead of the car's launch late next year, reveal the new coupé's lower suspension, wider wheel arches and distinctive quad-exhausts.

The M4 marks the beginnings of an expansion of the 3-series line-up. It replaces both the coupé and cabriolet variants of the M3 in favour of 4-series re-badging, leaving the M3 as a stand-alone four-door saloon. The marketing scheme mirrors that of the 5-series and 6-series, with BMW charging a premium for the more upscale model as it seeks to provide more distinct driving and styling experiences from the standard saloon models.

Both the M4 coupé and cabriolet variants of the 4-series are likely to share the M3's same basic structure and its new, turbocharged 3.0-litre six-cylinder engine. Weight-saving is likely to go one step further with the M4, however, with technical highlights such as a carbonfibre roof featuring in order to reduce weight and provide the lowest possible centre of gravity.

The M3 and M4 are expected during 2013, with an M4 Gran Coupé version expected to follow next year.

Tom Heron