Compare the2022 BMW M4VS 2021 Mercedes AMG C-Class Cabriolet

The M4 has a standard PostCrash iBrake, which automatically applies the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The AMG C-Class Cabriolet doesn’t offer a post collision braking system: in the event of a collision that triggers the airbags, more collisions are possible without the protection of airbags that may have already deployed.

Over 200 people are killed each year when backed over by motor vehicles. The M4 offers optional Active Park Distance Control that uses rear sensors to monitor and automatically apply the brakes to prevent a rear collision. The AMG C-Class Cabriolet doesn’t offer backup collision prevention brakes.

The M4’s standard lane departure warning system alerts a temporarily inattentive driver when the vehicle begins to leave its lane and gently nudges the vehicle back towards its lane. A lane departure warning system costs extra on the AMG C-Class Cabriolet.

To help make backing out of a parking space safer, the M4 has a standard cross-path warning system, which uses sensors in the rear bumper to alert the driver to vehicles approaching from the side, helping the driver avoid collisions. Cross-path warning costs extra on the AMG C-Class Cabriolet.

Both the M4 and the AMG C-Class Cabriolet have standard driver and passenger frontal airbags, front and rear side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, blind spot warning systems, rearview cameras and driver alert monitors.

The M4’s corrosion warranty is 7 years longer than the AMG C-Class Cabriolet’s (12 vs. 5 years).

BMW pays for scheduled maintenance on the M4 for 3 years and 36,000 miles. BMW will pay for oil changes, lubrication and any other required maintenance. Mercedes doesn’t pay scheduled maintenance for the AMG C-Class Cabriolet.

J.D. Power and Associates’ 2020 Initial Quality Study of new car owners surveyed provide the statistics that show that BMW vehicles are better in initial quality than Mercedes vehicles. J.D. Power ranks BMW 18th in initial quality. With 26 more problems per 100 vehicles, Mercedes is ranked 30th.

J.D. Power and Associates’ 2021 survey of the owners of three-year-old vehicles provides the long-term dependability statistics that show that BMW vehicles are more reliable than Mercedes vehicles. J.D. Power ranks BMW 10th in reliability, above the industry average. With 14 more problems per 100 vehicles, Mercedes is ranked 15th.

From surveys of all its subscribers, Consumer Reports’ January 2021 Auto Issue reports that BMW vehicles are more reliable than Mercedes vehicles. Consumer Reports ranks BMW 8 places higher in reliability than Mercedes.

The M4 has more powerful engines than the AMG C-Class Cabriolet:

Regenerative brakes improve the M4’s fuel efficiency by converting inertia back into energy instead of wasting it. The AMG C-Class Cabriolet doesn’t offer a regenerative braking system.

Both the M4 and the AMG C-Class Cabriolet have a standard automatic start/stop engine feature to stop unnecessary fuel waste and pollution at stop lights and heavy traffic. All M4s have a standard disable switch for the system, so a driver can keep the engine from shutting off when the vehicle stops temporarily.

For better stopping power the M4’s brake rotors are larger than those on the AMG C-Class Cabriolet:

The M4 stops shorter than the AMG C-Class Cabriolet:

For better traction, the M4 has larger tires than the AMG C-Class Cabriolet (F:275/40R18 & R:285/35R19 vs. F:225/45R18 & R:245/40R18). The M4’s front tires are larger than the largest tires available on the AMG C-Class Cabriolet (F:275/40R18 & R:285/35R19 vs. F:255/40R18 & R:285/35R18).

The M4’s standard 275/40R18 front and 285/35R19 rear tires provide better handling because they have a lower 40 series front and 35 series rear profile (height to width ratio) that provides a stiffer sidewall than the AMG C 43 Cabriolet’s standard 45 series front and 40 series rear tires.

For better ride, handling and brake cooling the M4 has standard 19-inch rear wheels. Smaller 18-inch wheels are standard on the AMG C 63 Cabriolet.

For better handling and stability, the track (width between the wheels) on the M4 is 1.2 inches wider in the rear than the average track on the AMG C-Class Cabriolet.

The BMW M4 may be more efficient, handle and accelerate better because it weighs up to about 400 pounds less than the Mercedes AMG C-Class Cabriolet.

The M4’s standard power retractable hardtop allows a seamless transition from an open car, to a completely sealed coupe. The AMG C-Class Cabriolet doesn’t offer a retractable hardtop.

The M4 Convertible has 2.7 cubic feet more passenger volume than the AMG C-Class Cabriolet (84 vs. 81.3).

The M4 Convertible has a much larger trunk with its top down than the AMG C-Class Cabriolet with its top down (10.6 vs. 7 cubic feet). The M4 Convertible has a much larger trunk with its top up than the AMG C-Class Cabriolet with its top up (13.6 vs. 8.8 cubic feet).

Pulling a handle automatically lowers the M4’s rear seats, to make changing between passengers and cargo easier. The AMG C-Class Cabriolet doesn’t offer automatic folding seats.

To make loading and unloading groceries and cargo easier when your hands are full, the M4’s trunk can be opened just by kicking your foot under the back bumper, leaving your hands completely free. The M4 also offers an optional power trunk, which opens and closes automatically by pressing a button. The AMG C-Class Cabriolet doesn’t offer a power or hands-free opening trunk.

On extremely cold winter days, the M4’s optional heated steering wheel provides comfort, allowing the driver to steer safely and comfortably before the car heater warms up. The AMG C-Class Cabriolet doesn’t offer a heated steering wheel.

The 4 Series was chosen as one of Car and Driver’s “Top Ten” in 2014. The AMG C-Class Cabriolet has never been a Car and Driver “Top Ten” pick.

The M3/M4 was chosen as one of Automobile Magazine’s “All Stars” for 13 of the last 25 years. The AMG C-Class Cabriolet has never been an “All Star.”