The Boxster offers optional Porsche Active Safe, which use forward mounted sensors to warn the driver of a possible collision ahead. If the driver doesn’t react and the system determines a collision is imminent, it automatically applies the brakes at full-force in order to reduce the force of the crash or avoid it altogether. The Z4 doesn't offer collision warning or crash mitigation brakes.
Both the Boxster and the Z4 have standard driver and passenger frontal airbags, front side-impact airbags, side-impact head airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control and electronic stability systems to prevent skidding.
J.D. Power and Associates rated the Boxster first among compact premium sporty cars in their 2013 Initial Quality Study. The Z4 was rated third.
J.D. Power and Associates’ 2013 Initial Quality Study of new car owners surveyed provide the statistics that show that Porsche vehicles are better in initial quality than BMW vehicles. J.D. Power ranks Porsche first in initial quality, above the industry average. With 34 more problems per 100 vehicles, BMW is ranked 18th, below the industry average.
J.D. Power and Associates’ 2013 survey of the owners of three-year-old vehicles provides the long-term dependability statistics that show that Porsche vehicles are more reliable than BMW vehicles. J.D. Power ranks Porsche second in reliability, above the industry average. With 39 more problems per 100 vehicles, BMW is ranked 16th.
As tested in Car and Driver the Boxster S is faster than the Z4 sDrive35i (manual transmissions tested):
Boxster |
Z4 |
|
Zero to 60 MPH |
4.4 sec |
4.8 sec |
Zero to 100 MPH |
10.5 sec |
11.7 sec |
Quarter Mile |
12.9 sec |
13.5 sec |
Speed in 1/4 Mile |
111 MPH |
106 MPH |
Top Speed |
176 MPH |
149 MPH |
As tested in Road & Track the Boxster S is faster than the BMW Z4 (automatics tested):
Boxster |
Z4 sDrive35i |
Z4 sDrive35is |
|
Zero to 30 MPH |
1.4 sec |
1.9 sec |
n/a |
Zero to 60 MPH |
4.1 sec |
4.8 sec |
4.4 sec |
Zero to 80 MPH |
6.7 sec |
7.8 sec |
n/a |
Zero to 100 MPH |
10.3 sec |
11.7 sec |
10.6 sec |
Quarter Mile |
12.6 sec |
13.3 sec |
12.9 sec |
Speed in 1/4 Mile |
109.7 MPH |
106.7 MPH |
109.9 MPH |
The flat cylinder configuration of the boxer engine in the Boxster lowers its center of gravity, enhancing handling stability. The Z4 doesn’t offer a boxer engine configuration.
On the EPA test cycle the Boxster gets better fuel mileage than the Z4:
Boxster |
Z4 |
|||
Base/Manual |
20 city/30 hwy |
19 city/26 hwy |
sDrive35i |
|
S/Manual |
20 city/28 hwy |
n/a |
||
Base/Auto |
22 city/32 hwy |
17 city/24 hwy |
sDrive35i |
|
S/Auto |
21 city/30 hwy |
17 city/24 hwy |
3Drive35is |
Regardless of its engine, the Boxster’s engine automatically turns off when the vehicle is stopped, saving fuel and reducing pollution. (Start/Stop isn’t accounted in present EPA fuel mileage tests.) BMW only offers an automatic engine start/stop system on the Z4 sDrive28i Manual.
The Boxster has 2.4 gallons more fuel capacity than the Z4 (16.9 vs. 14.5 gallons), for longer range between fill-ups.
The Boxster offers optional heat-treated ceramic brake rotors, which last ten to twenty times as long as conventional cast iron rotors, don’t rust, don’t fade during repeated high speed braking, and their lighter weight contribute to better braking, handling and acceleration. The Z4 doesn’t offer ceramic brake rotors.
The Boxster stops much shorter than the Z4:
Boxster |
Z4 |
||
80 to 0 MPH |
192 feet |
208 feet |
Road & Track |
70 to 0 MPH |
147 feet |
161 feet |
Car and Driver |
60 to 0 MPH |
112 feet |
122 feet |
Consumer Reports |
60 to 0 MPH (Wet) |
128 feet |
130 feet |
Consumer Reports |
For better traction, the Boxster has larger tires than the Z4 (F:235/45R18 & R:265/45R18 vs. 225/45R17). The Boxster’s tires are larger than the largest tires available on the Z4 (F:235/45R18 & R:265/45R18 vs. F:225/40R18 & R:255/35R18).
For better ride, handling and brake cooling the Boxster has standard 18-inch wheels. Smaller 17-inch wheels are standard on the Z4 sDrive28i. The Boxster’s optional 20-inch wheels are larger than the 19-inch wheels optional on the Z4 sDriver35i/sDrive35is.
The Boxster S handles at .99 G’s, while the Z4 sDrive35i pulls only .83 G’s of cornering force in a Car and Driver skidpad test.
The Boxster S goes through Road & Track’s slalom 3.2 MPH faster than the Z4 sDrive35i (69.4 vs. 66.2 MPH).
The Boxster S executes Motor Trend’s “Figure Eight” maneuver quicker than the Z4 sDrive35i (24.6 seconds @ .81 average G’s vs. 25.2 seconds @ .74 average G’s).
The Porsche Boxster may be more efficient, handle and accelerate better because it weighs about 400 to 550 pounds less than the BMW Z4.
The design of the Porsche Boxster amounts to more than styling. The Boxster offers aerodynamic coefficients of drag from .3 to .31 Cd (depending on bodystyle and options). That is significantly lower than the Z4 (.34 to .35) and many sports cars. A more efficient exterior helps keep the interior quieter and helps the Boxster get better fuel mileage.
As tested by Road & Track while cruising at 50 MPH, the interior of the Boxster S is quieter than the Z4 sDrive35i (68 vs. 72 dB).
The Boxster has .2 inches more front headroom and .8 inches more front legroom than the Z4.
The Boxster has a much larger trunk than the Z4 with its top down (9.9 vs. 6.4 cubic feet).
The Boxster’s instruments include an oil pressure gauge and a temperature gauge – which could save your engine! Often ‘idiot lights’ don’t warn you until damage has been done. The Z4 has neither an oil pressure gauge nor a temperature gauge.
Heated windshield washer nozzles are standard on the Boxster to prevent washer fluid and nozzles from freezing and help continue to keep the windshield clear in sub-freezing temperatures. The Z4 doesn’t offer heated windshield washer nozzles.
The Boxster’s optional air conditioned front seats cool the driver and front passenger and help take the sting out of hot leather in Summer. The Z4 doesn’t offer air conditioned front seats.
To keep a safe, consistent following distance, the Boxster PDK offers an optional Adaptive Cruise Control, which alters the speed of the vehicle without driver intervention. This allows the driver to use cruise control more safely without constantly having to disengage it when approaching slower traffic. The Z4 doesn’t offer an adaptive cruise control.
The Boxster will cost the buyer less in the long run because of its superior resale value. Kiplinger’s estimates that the Boxster will retain a greater percentage of its original price after three and five years than the Z4.
Boxster |
Z4 |
|
Five Year |
42% to 43% |
36% to 38% |
Three Year |
57% to 59% |
54% to 56% |
Intellichoice estimates that five-year ownership costs (depreciation, financing, insurance, fuel, fees, repairs and maintenance) for the Porsche Boxster will be $78 to $1937 less than for the BMW Z4.
The Porsche Boxster has won recognition from these important consumer publications:
Boxster |
Z4 |
|
Consumer Reports® Recommends |
TRUE |
n/a |
Intellichoice |
A “Best Value” |
no award |
Consumer Reports performed a comparison test in its June 2013 issue and they ranked the Porsche Boxster first. They ranked the BMW Z4 sDrive28i fourth.
J.D. Power and Associates rated the Boxster first among compact premium sporty cars in owner reported satisfaction. This includes how well the vehicle performs and satisfies its owner’s expectations. The Z4 was rated second.
The Boxster was chosen as one of Car and Driver’s “Top Ten” for 8 of the last 8 years. The Z4 has never been a Car and Driver “Top Ten” pick.
The Boxster was chosen as one of Automobile Magazine’s “All Stars” for 9 of the last 13 years. The Z4 hasn’t been picked since 2010.
The Porsche Boxster outsold the BMW Z4 by 84% during the 2013 model year.
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