2015 vs 2016 BMW M4

Both years

• Rod bearing wear All years One source so far

  What to check: Ask whether the rod bearings have been replaced, and when.

  Euro Premium Parts calls it the S55's most serious known issue, usually between 60,000 and 100,000 miles and sooner on hard-driven cars, and says many owners replace the bearings at around 50,000 miles.

  A seller's guide (unofficial)

• Cracked turbo oil feed lines All years One source so far

  What to check: Look for oil around the turbocharger housings.

  Euro Premium Parts says the lines can crack or leak between 40,000 and 80,000 miles, starving the turbos of oil.

  A seller's guide (unofficial)

• Cracked charge pipe All years One source so far

  What to check: Listen for a hiss and feel for lost power under boost, and ask whether the plastic charge pipes were replaced with metal or silicone ones.

  Euro Premium Parts says the factory plastic pipes commonly crack between 30,000 and 70,000 miles, especially on tuned cars.

  A seller's guide (unofficial)

• Electric water pump and thermostat All years One source so far

  What to check: Watch the temperature gauge, and ask whether the water pump has been replaced.

  Euro Premium Parts says the electric water pump can fail without warning between 50,000 and 80,000 miles and overheat the engine.

  A seller's guide (unofficial)

• Driveshaft recalls All years

  What to check: Make sure the driveshaft recalls were done.

  NHTSA lists a recall for driveshaft slip joints left without grease on some 2015 and 2016 cars, and one for the driveshaft-to-flange joint, which can fail and lose drive, on 2016 and 2017 cars including the GTS.

  NHTSA

• Worn front control arm bushings All years One source so far

  What to check: Listen for clunks over bumps and feel for vague steering.

  Euro Premium Parts says the bushings and ball joints wear faster than expected, between 40,000 and 70,000 miles.

  A seller's guide (unofficial)

Both years

• Rare M4 CS Trim

  A limited run, a third of it for the US CarGurus, a published reference

  1,000 built for United States, 33% of built worldwide A published reference

  Good or bad: CarGurus says it has a slightly less aggressive makeover than the GTS. CarGurus

Both years

• 15V782000 2015–2016

  The driveshaft's slip joint may not have been filled with grease and can fail over time. Dealers inspect the driveshaft and replace it if needed. NHTSA

• 16V653000 2015–2016

  During earlier rear differential service the rear subframe bolts may have been reused rather than replaced, and can loosen. Dealers fit new bolts. NHTSA

Both years

Engines

3.0L twin-turbo inline-six Edmunds, a published reference

Transmissions

Six-speed manual Edmunds, Seven-speed M-DCT dual-clutch Edmunds, CarGurus

Drivetrains

Rear-wheel drive Edmunds, CarGurus

Body styles

Coupe Edmunds, a published reference, Convertible Edmunds, a published reference

Trims

M4 CS CarGurus, a published reference

Packages

Executive Package Edmunds, Lighting Package (2015–2017) Edmunds, Driver Assistance Package (2015–2016) Edmunds

Both years

• Watch for: A car past 70,000 miles without records of the big jobs All years Less sought after One source so far

  Euro Premium Parts advises avoiding cars over 70,000 miles that cannot show recent rod bearing, water pump or charge pipe work, and being wary of track use, hard tuning or irregular oil changes at any mileage. A seller's guide (unofficial)