2017 BMW M23.0L Petrol

A whining rear differential or a heavy clonk when taking up drive is common on cars that have seen repeated launches or track work. Diff oil neglect and worn rear mounts make the problem worse.

The short wheelbase and stiff M chassis mean front tension struts, top mounts, and drop links take a beating on UK roads. Cars that have hit kerbs or potholes can feel nervous at motorway speed.

N55 and S55-powered cars can develop boost leaks from cracked plastic charge pipes or split boost joints, especially on mapped cars. Power drops off sharply when this happens.