■ Engine: Some specialists report failing big ends. It’s not mileage-related and the advice is to have them replaced before they fail – it costs around £1500. Infrequent oil changes is a possible reason. Poor throttle response could be failing throttle actuators, uneven tickover is faulty ignition coils and lumpy acceleration a faulty injector. Check the oil level using iDrive.
■ Transmission: Manual and DCT gearboxes are tough but extreme driving modes for the transmission and rear diff stored in the iDrive system suggest a hard-driven car, so check all works as it should. The DCT is sealed for life but a 60,000- mile oil and filter change doesn’t hurt. In any case, its plastic sump becomes brittle over time and weeps oil. A fluid and sump change costs around £500.
■ Suspension and brakes: Check the optional EDC dampers for leaks. The M3 is heavy so feel for worn bushes and general looseness over bumps. Check rear brakes for seized pistons; check tyres for uneven wear. Factor in the cost of a geometry check of the fully adjustable suspension.
■ Bodywork: Any rust suggests a crash repair. Check wing bolts for fresh paint, lift the boot carpet and check for buckling and examine the headlights for water ingress (it’s increasingly common).
■ Interior: Make sure all the modes and driver aids (throttle response, steering, gearshift, EDC damper control, traction control) operate. Key settings reveal a lot about the previous owner’s driving style.
Also worth knowing
You can check the service status of the oil, brake pads and fluid and cabin microfilter via the dash information centre on early cars and iDrive on later ones. The key also stores the service history: put it in the ignition and check what’s been done and what’s due.
How much to spend
£12,500-£13,999: Early high and average-mile coupés and cabrios with varying histories, including a 2007 coupé with 99k miles and good history for £12,750.
£14,000-£15,999: Lower-mileage cars up to 2009-reg with good histories and loads of extras.
£16,000-£18,499: Cleaner low-mileage cars, many with full BMW histories and up to 2010-reg.
£18,500-£20,999: More mid-mileage (50k) 2009 to 11-reg cars.
£21,000-£23,999: Low-mileage 2011 to 12-reg cars.