Compare the2023 BMW Z4VS 2023 Porsche 718 Boxster

The Z4’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The 718 Boxster doesn’t offer pre-crash pretensioners.

The Z4 has standard Post-Crash Braking, which automatically apply the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The 718 Boxster 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.

The Z4’s optional lane departure warning system alerts a temporarily inattentive driver when the vehicle begins to leave its lane. The 718 Boxster doesn’t offer a lane departure warning system.

To help make backing out of a parking space safer, the Z4’s optional Cross Traffic Warning uses sensors in the rear to alert the driver to vehicles approaching from the side, helping the driver avoid collisions. The 718 Boxster doesn’t offer a rear cross-path warning system.

The Z4’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 718 Boxster doesn’t offer a driver alert monitor.

Both the Z4 and the 718 Boxster 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, rearview cameras, available blind spot warning systems and rear parking sensors.

BMW pays for scheduled maintenance on the Z4 for 2 years and 26000 miles longer than Porsche pays for maintenance for the 718 Boxster (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 Z4’s warranty.

To reliably start during all conditions and help handle large electrical loads, the Z4 has a standard 800-amp battery (900 M40i). The 718 Boxster’s 450-amp battery isn’t as powerful.

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 Z4 has more powerful engines than the 718 Boxster:

As tested in Car and Driver the Z4 M40i 3.0 turbo 6-cylinder is faster than the Porsche 718 Boxster turbo 4 cyl. (automatics tested):

On the EPA test cycle the Z4 gets better mileage than the 718 Boxster:

In its Green Vehicle Guide, the U.S. Environmental Protection Agency (EPA) rates the BMW Z4 higher (5 to 7 out of 10) than the Porsche 718 Boxster (1 to 5). This means the Z4 produces up to 47 pounds less smog-producing pollutants than the 718 Boxster every 15,000 miles.

The BMW Z4 comes standard with an automatic transmission, for driver comfort, especially in the city. Automatic costs extra on the 718 Boxster.

An eight-speed automatic is standard on the BMW Z4, for better acceleration and lower engine speed on the highway. Only a seven-speed automatic is available for the 718 Boxster.

The Z4 stops shorter than the 718 Boxster:

For better traction, the Z4’s optional front tires are larger than the largest tires available on the 718 Boxster (255/35R19 vs. 245/35R20).

The Z4’s standard 255/40R18 rear tires provide better handling because they have a lower 40 series profile (height to width ratio) that provides a stiffer sidewall than the 718 Boxster’s standard 45 series tires.

For better handling and stability, the average track (width between the wheels) on the Z4 is 3.3 inches wider in the front and 2.6 inches wider in the rear than the average track on the 718 Boxster.

The Z4’s front to rear weight distribution is more even (51.2% to 48.8%) than the 718 Boxster’s (45.5% to 54.5%). This gives the Z4 more stable handling and braking.

The Z4 M40i handles at 1.02 G’s, while the 718 Boxster pulls only 1.01 G’s of cornering force in a Car and Driver skidpad test.

For better maneuverability, the Z4’s turning circle is .1 feet tighter than the 718 Boxster’s (36 feet vs. 36.1 feet). The Z4’s turning circle is 1.5 feet tighter than the 718 Spyder’s (36 feet vs. 37.5 feet).

The design of the BMW Z4 amounts to more than styling. The Z4 offers aerodynamic coefficients of drag from .29 to .31 Cd (depending on bodystyle and options). That is lower than the 718 Boxster (.31 to .34) and many sports cars. A more efficient exterior helps keep the interior quieter and helps the Z4 get better fuel mileage.

As tested by Car and Driver, the interior of the Z4 sDrive30i is quieter than the 718 Boxster S:

The Z4 has 3 cubic feet more passenger volume than the 718 Boxster (52 vs. 49).

The Z4 has a larger trunk with its top down than the 718 Boxster (9.9 vs. 9.6 cubic feet).

With its convertible body style, valet key and remote trunk release lockout, the Z4 offers cargo security. The 718 Boxster’s non-lockable remote release defeats cargo security.

The Z4 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 718 Boxster doesn’t offer a remote starting system.

Unlike the driver-only memory system optional at extra cost in the 718 Boxster, the Z4 has standard driver and passenger memory, so that when drivers switch, the memory setting adjusts the driver’s seat, outside mirror angle, climate settings and radio stations and the front passenger seat also adjusts to the new passenger’s preset preferences.

The Z4 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 718 Boxster doesn’t offer a heads-up display.

If the windows are left open on the Z4 the driver can close them all from a distance using the remote. On a hot day the driver can also lower the windows the same way. The driver of the 718 Boxster can only operate the windows from inside the vehicle, with the ignition on.

The Z4’s power window, power lock, power mirror and cruise control switches are lit from behind, making them plainly visible and easier to operate at night. The 718 Boxster’s cruise control switches are unlit, making them difficult to find at night and operate safely.

The Z4’s LED headlights produce a white, bright light using less electricity than the 718 Boxster’s standard xenon high intensity discharge (HID) headlights. HID headlights can be slow to reach full brightness or power cycle, causing issues when flashing them to signal other vehicles; LED headlights light instantly. LED lights also last about three to four times as long.

The Z4’s sun-visors swivel front-to-side to block glare from the side windows. The 718 Boxster’s visors are fixed into the windshield header.

To quickly and conveniently keep personal devices charged without cables tangling and wearing out, the BMW Z4 offers an optional wireless phone charging system (Qi) in the center console. The 718 Boxster doesn’t offer wireless personal charging.

The Z4’s optional Parking Assistant can parallel park by itself, with the driver only controlling speed with the brake pedal. The 718 Boxster doesn’t offer an automated parking system.

Insurance will cost less for the Z4 owner. The Complete Car Cost Guide estimates that insurance for the Z4 will cost $890 less than the 718 Boxster over a five-year period.

IntelliChoice estimates that five-year ownership costs (depreciation, financing, insurance, fuel, fees, repairs and maintenance) for the BMW Z4 will be $7017 to $18629 less than for the Porsche 718 Boxster.

Consumer Reports® recommends both the BMW Z4 and the Porsche 718 Boxster, based on reliability, safety and performance.