Certified Benz & Beemer Compares 2006 Porsche BOXSTER VS 2006 BMW Z4 Near Scottsdale, AZ

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2006 Porsche BOXSTER

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2006 BMW Z4

Safety Comparison

The Boxster has standard head airbag curtains which act as a forgiving barrier between the driver and outboard passenger's upper bodies and the window and pillars. Combined with high-strength steel door beams and lower side airbags this system increases head protection in broadside collisions. The Z4 doesn't offer side airbag protection for the head.

The Boxster offers an optional backup radar to help warn drivers about vehicles, pedestrians or other obstacles behind their vehicle. This collision warning system uses radar to detect obstacles behind the rear bumper. The Z4 doesn’t offer a rear collision sensor.

Both the Boxster and the Z4 have standard driver and passenger frontal airbags, front side-impact airbags, front seatbelt pretensioners, four wheel antilock brakes, traction control and electronic stability systems to prevent skidding.

Engine Comparison

The Boxster’s standard 2.7 DOHC 6 cyl. produces 25 more horsepower (240 vs. 215) and 14 lbs.-ft. more torque (199 vs. 185) than the Z4 3.0i Roadster’s standard 3.0 DOHC 6 cyl. The Boxster S’ standard 3.2 DOHC 6 cyl. produces 25 more horsepower (280 vs. 255) and 16 lbs.-ft. more torque (236 vs. 220) than the Z4 3.0si’s standard 3.0 DOHC 6 cyl.

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.

Fuel Economy and Range Comparison

The Boxster has 2.4 gallons more fuel capacity than the Z4 (16.9 vs. 14.5 gallons), for longer range between fill-ups.

Brakes and Stopping Comparison

For better stopping power the Boxster S’ brake rotors are larger than those on the Z4:

Boxster S

Z4 3.0i Roadster

Z4 3.0si

Front Rotors

13.78 inches

11.8 inches

12.8 inches

Rear Rotors

11.77 inches

11.6 inches

11.6 inches

The Boxster S 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 shorter than the Z4:



80 to 0 MPH

187 feet

196 feet

Road & Track

70 to 0 MPH

153 feet

161 feet

Car and Driver

60 to 0 MPH

107 feet

113 feet

Road & Track

Tires and Wheels Comparison

For better traction, the Boxster’s optional tires are larger than the largest tires available on the Z4 (F:235/40R18 & R:265/40R18 vs. F:225/40R18 & R:255/35R18).

For better ride, handling and brake cooling the Boxster offers optional 19 inch wheels. The Z4’s largest wheels are only 18 inches.

Suspension and Handling Comparison

The Boxster offers an optional driver-adjustable suspension system. It allows the driver to choose between an extra-supple ride, reducing fatigue on long trips, or a sport setting, which allows maximum control for tricky roads. The Z4’s suspension doesn’t offer adjustable shock absorbers.

The Boxster S handles at .97 G’s, while the Z4 3.0si Roadster pulls only .88 G’s of cornering force in a Motor Trend skidpad test.

The Boxster S goes through Road & Track’s slalom 6.9 MPH faster than the Z4 3.0si Roadster (73.9 vs. 67 MPH).

Chassis Comparison

To almost totally eliminate engine vibration in the passenger area, the Boxster has liquid-filled engine mounts. The liquid helps further dampen engine harshness. The Z4 uses conventional solid rubber engine mounts.

The design of the Porsche Boxster amounts to more than styling. The Boxster offers aerodynamic coefficients of drag from .29 to .3 Cd (depending on bodystyle and options). That is significantly lower than the Z4 (.34 to .36) and many sports cars. A more efficient exterior helps keep the interior quieter and helps the Boxster get better fuel mileage.

Passenger Space Comparison

The Boxster has 1 inch more front headroom and 1 inch more front legroom than the Z4.

Cargo Capacity Comparison

The Boxster has a larger trunk than the Z4 Roadster with its top down (9.5 vs. 8.5 cubic feet). The Boxster has a larger trunk than the Z4 Roadster with its top up (9.5 vs. 9.2 cubic feet).

A standard locking glovebox keeps your small valuables safer in the Boxster. The Z4 doesn’t offer locking storage for small valuables.

Ergonomics Comparison

The Boxster’s front power windows raise and lower automatically with one touch, especially convenient at tollbooths or drive-up windows. Only the driver’s window of the Z4 works automatically with one touch.

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