2020 BMW 4 Series Convertible vs. 2019 Ford Mustang

Detailed Review, Specifications & Comparison

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The 4 Series Convertible offers all-wheel drive to maximize traction under poor conditions, especially in ice and snow. The Mustang doesn’t offer all-wheel drive.

The 4 Series Convertible offers an optional Side and Top View Cameras to allow the driver to see objects all around the vehicle on a screen. The Mustang only offers a rear monitor and rear parking sensors that beep or flash a light. That doesn’t help with obstacles to the front or sides.

Both the 4 Series Convertible and the Mustang have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, daytime running lights and rearview cameras.


The 4 Series Convertible comes with a full 4-year/50,000-mile basic warranty, which covers the entire car and includes 24-hour roadside assistance. The Mustang’s 3-year/36,000-mile basic warranty expires 1 year and 14,000 miles sooner.

The 4 Series Convertible’s corrosion warranty is 7 years longer than the Mustang’s (12 vs. 5 years).

BMW pays for scheduled maintenance on the 4 Series Convertible for 3 years and 36,000 miles. BMW will pay for oil changes, lubrication and any other required maintenance. Ford doesn’t pay scheduled maintenance for the Mustang.


The battery on the 4 Series Convertible is in the trunk, which protects it from hot underhood temperatures that can degrade battery life. By keeping the 4 Series Convertible’s battery 20 to 30 degrees cooler, its life is increased by years. The Mustang’s battery is in the hot engine compartment.

A reliable vehicle saves its owner time, money and trouble. Nobody wants to be stranded or have to be without a vehicle while it’s being repaired. Consumer Reports rates the 4 Series Convertible’s reliability 54 points higher than the Mustang.

J.D. Power and Associates’ 2019 survey of the owners of three-year-old vehicles provides the long-term dependability statistics that show that BMW vehicles are more reliable than Ford vehicles. J.D. Power ranks BMW 7th in reliability, above the industry average. With 24 more problems per 100 vehicles, Ford is ranked 16th.

From surveys of all its subscribers, Consumer Reports’ December 2018 Auto Issue reports that BMW vehicles are more reliable than Ford vehicles. Consumer Reports ranks BMW 10 places higher in reliability than Ford.

Fuel Economy and Range

On the EPA test cycle the 4 Series Convertible gets better fuel mileage than the Mustang Convertible:


4 Series Convertible



430i 2.0 turbo 4 cyl.

23 city/34 hwy

440i 3.0 turbo 6 cyl.

22 city/29 hwy



430i 2.0 turbo 4 cyl.

22 city/32 hwy

440i 3.0 turbo 6 cyl.

20 city/28 hwy

Mustang Convertible



2.3 turbo 4 cyl.

20 city/28 hwy

Performance 2.3 turbo 4 cyl.

20 city/27 hwy

5.0 DOHC V8

14 city/21 hwy


2.3 turbo 4 cyl.

20 city/28 hwy

Performance 2.3 turbo 4 cyl.

20 city/28 hwy

5.0 DOHC V8

15 city/24 hwy

Regenerative brakes improve the 4 Series Convertible’s fuel efficiency by converting inertia back into energy instead of wasting it. The Mustang doesn’t offer a regenerative braking system.

In heavy traffic or at stoplights the 4 Series Convertible’s engine automatically turns off when the vehicle is stopped, saving fuel and reducing pollution. The engine is automatically restarted when the driver gets ready to move again. (Start/Stop isn’t accounted in present EPA fuel mileage tests.) The Mustang doesn’t offer an automatic engine start/stop system.

Transmission and Drivetrain

The BMW 4 Series Convertible comes standard with an automatic transmission, for driver comfort, especially in the city. Automatic costs extra on the Mustang.

All wheel drive, available in the 4 Series Convertible, provides the best traction for acceleration in wet, dry, and icy conditions. In corners, all wheel drive allows both outside wheels to provide power, balancing the car. This allows for better handling. The Ford Mustang is not available with all wheel drive.

Brakes and Stopping

For better stopping power the 4 Series Convertible’s standard front brake rotors are larger than those on the Mustang:

4 Series


Front Rotors

13 inches

12.6 inches

Tires and Wheels

The 4 Series Convertible’s standard tires provide better handling because they have a lower 45 series profile (height to width ratio) that provides a stiffer sidewall than the Mustang’s standard 55 series tires.

For better ride, handling and brake cooling the 4 Series Convertible has standard 18-inch wheels. Smaller 17-inch wheels are standard on the Mustang.

Changing a flat tire near traffic can be dangerous and inconvenient. The run-flat tires standard on the 4 Series Convertible can be driven up to 50 miles without any air pressure, allowing you to drive to a service station for a repair. The Mustang doesn’t offer run-flat tires.

Suspension and Handling

For a smoother ride and more stable handling, the 4 Series Convertible’s wheelbase is 3.5 inches longer than on the Mustang (110.6 inches vs. 107.1 inches).

The 4 Series Convertible’s front to rear weight distribution is more even (49% to 51%) than the Mustang’s (54.7% to 45.3%). This gives the 4 Series Convertible more stable handling and braking.


The 4 Series Convertible is 5.8 inches shorter than the Mustang, making the 4 Series Convertible easier to handle, maneuver and park in tight spaces.

The 4 Series Convertible’s standard power retractable hardtop allows a seamless transition from an open car, to a completely sealed coupe. The Mustang doesn’t offer a retractable hardtop.

Passenger Space

The 4 Series Convertible has 10.7 cubic feet more passenger volume than the Mustang Convertible (90 vs. 79.3).

Cargo Capacity

The 4 Series Convertible has a much larger trunk with its top up than the Mustang Convertible (13.1 vs. 11.4 cubic feet).

The 4 Series Convertible’s standard rear seats fold to accommodate long and bulky cargo. The Mustang Convertible doesn’t offer folding rear seats.

To make loading groceries and cargo easier when your hands are full, the 4 Series Convertible’s available trunk can be opened just by kicking your foot under the back bumper, leaving your hands completely free. The Mustang doesn’t offer a hands-free gesture to open its trunk, forcing you to put cargo down if your hands are full.

Servicing Ease

The 4 Series Convertible uses gas struts to support the hood for easier service access. The Mustang uses a prop rod to support its heavy hood. It takes two hands to open the hood and set the prop rod, the prop rod gets in the way during maintenance and service, and the prop rod could be knocked out, causing the heavy hood to fall on the person maintaining or servicing the car.


The 4 Series Convertible 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 Mustang doesn’t offer a heads-up display.

The 4 Series Convertible’s front and rear power windows all open or close fully with one touch of the switches, making it more convenient at drive-up windows and toll booths, or when talking with someone outside the car. The Mustang’s rear power window switches have to be held the entire time to open or close them fully.

If the windows are left open on the 4 Series Convertible the driver can close them all at the outside door handle. On a hot day the driver can lower the windows at the outside door handle or from a distance using the keyless remote. The driver of the Mustang can only close the windows from inside the vehicle, with the ignition on.

The 4 Series Convertible has a standard locking fuel door with a remote release located convenient to the driver. A locking fuel door helps prevent vandalism, such as sugar in the tank and fuel theft. The Mustang doesn’t offer a locking fuel door.

The 4 Series Convertible’s rain-sensitive wipers adjust their speed and turn on and off automatically based on the amount of rainfall on the windshield. This allows the driver to concentrate on driving without constantly adjusting the wipers. The Mustang’s standard intermittent wipers change speed with vehicle speed, but can’t turn on and off or change speed based on changing rainfall.

Heated windshield washer nozzles are standard on the 4 Series Convertible to prevent washer fluid and nozzles from freezing and help continue to keep the windshield clear in sub-freezing temperatures. The Mustang doesn’t offer heated windshield washer nozzles.

To help drivers see further while navigating curves, the 4 Series Convertible offers optional adaptive headlights to illuminate around corners automatically by reading vehicle speed and steering wheel angle. The Mustang doesn’t offer cornering lights.

When the 4 Series Convertible is put in reverse, the passenger rearview mirror tilts from its original position. This gives the driver a better view of the curb during parallel parking maneuvers. Shifting out of reverse puts the mirror into its original position. The Mustang’s mirror doesn’t automatically adjust for backing.

The 4 Series Convertible has standard automatic dimming rear and side view mirrors which automatically darken quickly when headlights shine on them, keeping following vehicles from blinding or distracting the driver. The Mustang has an automatic rear view mirror, but its side mirrors don’t dim.

The 4 Series Convertible has a standard dual zone air conditioning allows the driver and front passenger to choose two completely different temperatures so people with different temperature preferences won’t have to compromise. This makes both the driver and front passenger as comfortable as possible. Dual zone air conditioning costs extra on the Mustang.

For greater rear passenger comfort, the 4 Series Convertible has standard rear a/c vents to keep rear occupants more comfortable. The Mustang doesn’t offer rear vents.

The 4 Series Convertible’s optional Parking Assistant can parallel park or back into a parking spot by itself, with the driver only controlling speed with the brake pedal. The Mustang doesn’t offer an automated parking system.

Model Availability

The BMW 4 Series comes in coupe, convertible and four-door hatchback bodystyles; the Ford Mustang isn’t available as a four-door.

Economic Advantages

Insurance will cost less for the 4 Series Convertible owner. The Car Book by Jack Gillis rates the 4 Series Convertible with a number “1” insurance rate while the Mustang is rated higher at a number “3” rate.

According to The Car Book by Jack Gillis, the 4 Series Convertible is less expensive to operate than the Mustang because typical repairs cost much less on the 4 Series Convertible than the Mustang, including $27 less for a muffler and $532 less for a power steering pump.


The 4 Series Convertible was chosen as one of Automobile Magazine’s “All Stars” in 2014. The Mustang has never been an “All Star.”

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

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