2020 BMW M4 vs. 2019 Porsche 911

Detailed Review, Specifications & Comparison

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The M4’s lane departure warning system alerts a temporarily inattentive driver when the vehicle begins to leave its lane. The 911 doesn’t offer a lane departure warning system.

The M4 offers an optional Side and Top View Cameras to allow the driver to see objects all around the vehicle on a screen. The 911 only offers a rear monitor and front and rear parking sensors that beep or flash a light. That doesn’t help with obstacles to the sides.

Both the M4 and the 911 have standard driver and passenger frontal airbags, front 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, daytime running lights, rearview cameras and available blind spot warning systems.


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


To reliably power the ignition and other systems and to recharge the battery, the M4 has a 209-amp alternator. The 911’s standard 204-amp alternator isn’t as powerful.

From surveys of all its subscribers, Consumer Reports’ December 2018 Auto Issue reports that BMW vehicles are more reliable than Porsche vehicles. Consumer Reports ranks BMW 3 places higher in reliability than Porsche.


As tested in Road and Track the BMW M4 (base engine) is faster than the Porsche 911 (base engine) (manual transmissions tested):



Zero to 30 MPH

1.5 sec

1.7 sec

Zero to 60 MPH

3.9 sec

4.1 sec

Zero to 80 MPH

6.3 sec

6.5 sec

Zero to 100 MPH

9.1 sec

9.3 sec

Quarter Mile

12.3 sec

12.4 sec

Environmental Friendliness

In its Green Vehicle Guide, the U.S. Environmental Protection Agency (EPA) rates the BMW M4 higher (3 out of 10) than the Porsche 911 (1). This means the M4 produces up to 22.5 pounds less smog-producing pollutants than the 911 every 15,000 miles.

Brakes and Stopping

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



Front Rotors

15 inches

13 inches

Rear Rotors

14.6 inches

13 inches

The M4 stops shorter than the 911:



80 to 0 MPH

193 feet

197 feet

Road and Track

60 to 0 MPH

106 feet

113 feet

Road and Track

Tires and Wheels

For better traction, the M4 has larger front standard tires than the 911 (255/40R18 vs. 235/40R19).

The M4’s optional tires provide better handling because they have a lower 30 series profile (height to width ratio) that provides a stiffer sidewall than the 911’s optional 35 series front tires.

Suspension and Handling

For a smoother ride and more stable handling, the M4’s wheelbase is 14.2 inches longer than on the 911 (110.7 inches vs. 96.5 inches). The M4’s wheelbase is 14 inches longer than on the 911 GT3 (110.7 feet 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 1.9 inches wider in the rear than the average track on the 911.

The M4’s front to rear weight distribution is more even (48.1% to 51.9%) than the 911’s (40.1% to 59.9%). This gives the M4 more stable handling and braking.


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 GT2 RS:



At idle

48 dB

68 dB


87 dB

95 dB

70 MPH Cruising

68 dB

79 dB

Passenger Space

Because it has more passenger and cargo room, the EPA rates the M4 Coupe a Compact car, while the 911 Coupe is rated a Minicompact. The EPA rates the M4 Convertible a Subcompact car, while the 911 Cabriolet is rated a Minicompact.

The M4 Coupe has 20.2 cubic feet more passenger volume than the 911 Coupe (90.2 vs. 70). The M4 Convertible has 21.9 cubic feet more passenger volume than the 911 Cabriolet (89.9 vs. 68).

The M4 Coupe has 1.8 inches more front headroom, 4.5 inches more front shoulder room, 5.1 inches more rear headroom, 8.7 inches more rear legroom and 3.4 inches more rear shoulder room than the 911 Coupe.

The M4 Convertible has 2.4 inches more front headroom, 4.5 inches more front shoulder room and 6.1 inches more rear headroom than the 911 Cabriolet.

Cargo Capacity

The M4 Coupe has a much larger trunk than the 911 Coupe with its rear seat up (11 vs. 5.1 cubic feet). The M4 has a much larger trunk with its rear seat folded than the 911 Coupe with its rear seat folded (11 vs. 9.1 cubic feet).

The M4 Convertible has a much larger trunk with its top down than the 911 Cabriolet (7.8 vs. 5.1 cubic feet). The M4 Convertible has a much larger trunk with its top up than the 911 Cabriolet (11 vs. 5.1 cubic feet).

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

To make loading groceries and cargo easier when your hands are full, just kicking your foot under the back bumper can open the M4’s trunk, leaving your hands completely free. The 911 doesn’t offer a hands-free gesture to open its trunk, forcing you to put cargo down if your hands are full.


The M4 offers an optional heads-up display that projects speed and other key instrumentation 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. 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. 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.

Comfort Access standard on the M4 allows you to unlock the driver’s door, trunk and start the engine all without removing a key from pocket or purse. This eliminates searching for keys before loading groceries, getting in the vehicle in bad weather or making a hurried start to your trip. The Porsche 911’s available Porsche Entry and Drive doesn’t unlock the trunk.

Heated windshield washer nozzles are standard on the M4 to prevent washer fluid and nozzles from freezing and help continue to keep the windshield clear in sub-freezing temperatures. The 911 doesn’t offer heated windshield washer nozzles.

A power rear sunshade is optional in the M4 Coupe to help block heat and glare for the rear passengers. The 911 doesn’t offer a rear sunshade.

For greater rear passenger comfort, the M4 has standard rear a/c vents to keep rear occupants more comfortable. The 911 doesn’t offer rear vents.

The M4’s optional Parking Assistant can parallel park by itself, with the driver only controlling speed with the brake pedal. The 911 doesn’t offer an automated parking system.

Economic Advantages

IntelliChoice estimates that five-year ownership costs (depreciation, financing, insurance, fuel, fees, repairs and maintenance) for the BMW M4 will be $12616 to $82137 less than for the Porsche 911.


The 4 Series was chosen as one of Car and Driver’s “Top Ten” in 2014. The 911 has never been a Car and Driver “Top Ten” pick.

© 1991-2018 Advanta-STAR Automotive Research. All rights reserved.

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