Compare the2023 BMW M4VS 2023 Porsche 911

The M4’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The 911 doesn’t offer pre-crash pretensioners.

The BMW M4 has standard driver and front passenger side knee airbags mounted low on the dashboard. These airbags helps prevent the driver and front passenger from sliding under their seatbelts or the main frontal airbags; this keeps them better positioned during a collision for maximum protection. Knee airbags also help keep the legs from striking the dashboard, preventing knee and leg injuries in the case of a serious frontal collision. The 911 doesn’t offer knee airbags.

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 911 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 an optional Active Park Distance Control that uses rear sensors to monitor for objects to the rear and automatically applies the brakes to prevent a collision. The 911 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 911.

The M4 has a standard blind spot warning system that uses sensors to alert the driver to objects in the vehicle’s blind spots where the side view mirrors don’t reveal them and moves the vehicle back into its lane. A system to reveal vehicles in the 911’s blind spot costs extra.

To help make backing out of a parking space safer, the M4’s standard Cross Traffic Warning uses sensors in the rear to alert the driver to vehicles approaching from the side, helping the driver avoid collisions. The 911 doesn’t offer a rear cross-path warning system.

The M4’s driver alert monitor detects an inattentive driver then sounds a warning and suggests a break. According to the NHTSA, drivers who fall asleep cause about 100,000 crashes and 1500 deaths a year. The 911 doesn’t offer a driver alert monitor.

Both the M4 and the 911 have standard driver and passenger frontal airbags, front side-impact airbags, side-impact head airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, daytime running lights, rearview cameras and available around view monitors.

BMW pays for scheduled maintenance on the M4 for 2 years and 26000 miles longer than Porsche pays for maintenance for the 911 (3/36,000 vs. 1/10,000).

There are over 80 percent more BMW dealers than there are Porsche dealers, which makes it much easier should you ever need service under the M4’s warranty.

J.D. Power and Associates’ 2022 Initial Quality Study of new car owners surveyed provide the statistics that show that BMW vehicles are better in initial quality than Porsche vehicles. J.D. Power ranks BMW above average in initial quality. With 35 more problems per 100 vehicles, Porsche is rated below average.

The M4 has more powerful engines than the 911:

As tested in Car and Driver the M4 CSL is faster than the Porsche 911 3.0 turbo 6-cylinder (automatics tested):

On the EPA test cycle the M4 Coupe gets better mileage than the 911 Coupe:

On the EPA test cycle the M4 Convertible gets better mileage than the 911 Cabriolet:

Regenerative brakes improve the M4’s fuel efficiency by converting inertia back into energy instead of wasting it. The 911 doesn’t offer a regenerative braking system.

In its Green Vehicle Guide, the U.S. Environmental Protection Agency (EPA) rates the BMW M4 higher (5 out of 10) than the Porsche 911 (3 to 5). This means the M4 produces up to 16.5 pounds less smog-producing pollutants than the 911 every 15,000 miles.

For better stopping power the M4’s standard brake rotors are larger than those on the 911:

For better traction, the M4 has larger front tires than the 911 (275/40R18 vs. 235/40R19). The M4’s front tires are larger than the largest tires available on the 911 (275/40R18 vs. 255/35R20).

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 911 Dakar’s standard 45 series front and 40 series rear tires.

For a smoother ride and more stable handling, the M4’s wheelbase is 16 inches longer than on the 911 (112.5 inches vs. 96.5 inches). The M4’s wheelbase is 15.8 inches longer than on the 911 GT3 (112.5 inches vs. 96.7 inches).

For better handling and stability, the track (width between the wheels) on the M4 is 1.1 inches wider in the front and 1.6 inches wider in the rear than the average track on the 911.

The M4’s front to rear weight distribution is more even (51% to 49%) than the 911’s (39.5% to 60.5%). This gives the M4 more stable handling and braking.

The M4 CSL handles at 1.10 G’s, while the 911 Carrera 4 GTS pulls only 1.03 G’s of cornering force in a Car and Driver skidpad test.

The M4’s standard power retractable hardtop allows a seamless transition from an open car, to a completely sealed coupe. The 911 doesn’t offer a retractable hardtop.

As tested by Car and Driver, the interior of the M4 Coupe is quieter than the 911 Turbo S Coupe:

The M4 Coupe has 18 cubic feet more passenger volume than the 911 (91 vs. 73).

The M4 Coupe has 2.4 inches more front headroom, 2.5 inches more front shoulder room, 3.3 inches more rear headroom, 7.5 inches more rear legroom and 3.1 inches more rear shoulder room than the 911 Coupe.

The M4 Coupe has a much larger trunk than the 911 Coupe with its rear seat up (12 vs. 4.6 cubic feet).

The M4 Convertible has a much larger trunk with its top down than the 911 Cabriolet with its top down (10.6 vs. 4.6 cubic feet). The M4 Convertible has a much larger trunk with its top up than the 911 Cabriolet with its top up (13.6 vs. 10.4 cubic feet).

With its coupe body style, valet key, locking rear seatbacks and remote trunk release lockout, the M4 offers cargo security. The 911’s non-lockable folding seat defeats cargo security.

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 911 doesn’t offer a power or hands-free opening trunk.

The M4 (except Manual) offers a remote vehicle starting system, so the vehicle can be started from inside the driver's house. This allows the driver to comfortably warm up the engine before going out to the vehicle. The climate system will also automatically heat or cool the interior. The 911 doesn’t offer a remote starting system.

The M4 offers an optional heads-up display that projects speed, tachometer, warning and navigation instruction readouts in front of the driver’s line of sight, allowing drivers to view information without diverting their eyes from the road. The 911 doesn’t offer a heads-up display.

If the windows are left open on the M4 the driver can close them all at the outside door handle or from a distance using the remote. On a hot day the driver can lower the windows from a distance using the keyless remote. The driver of the 911 can only operate the windows from inside the vehicle, with the ignition on.

In case of a sudden change of weather, the M4 has a standard remote convertible top that can be raised from a distance to protect the interior of the vehicle from damage. On a hot day the M4 has a standard remote opening feature, to lower the top from outside. The 911 doesn’t offer a remote top, so the driver will have to run to the car, get in, turn the ignition on and raise the top to prevent the interior from being damaged.

To quickly and conveniently keep personal devices charged without cables tangling and wearing out, the BMW M4 offers an optional wireless phone charging system (Qi) in the center console. The 911 doesn’t offer wireless personal charging.

IntelliChoice estimates that five-year ownership costs (depreciation, financing, insurance, fuel, fees, repairs and maintenance) for the BMW M4 will be $9335 to $78834 less than for the Porsche 911.

The 4 Series was chosen as a Car and Driver’s “Top Ten” for 2014. The 911 has never been chosen by Car and Driver in their “10Best” issue.

The BMW 4 Series outsold the Porsche 911 by almost five to one during 2022.