The Cayenne offers an optional collision warning system, which detects an impending crash through forward mounted sensors and flashes a bright light and sounds a loud, distinctive tone to warn the driver to brake or maneuver immediately to avoid a collision. The system also pre-charges the brakes to begin deceleration more quickly. The GLK doesn't offer a collision warning system.
To provide maximum traction and stability on all roads, All Wheel Drive is standard on the Cayenne. But it costs extra on the GLK.
When descending a steep, off-road slope, the Cayenne’s standard Porsche Hill Control allows you to creep down safely. The GLK doesn’t offer Porsche Hill Control.
The Cayenne’s optional blind spot warning system uses digital cameras monitored by computer to alert the driver to moving objects in the vehicle’s blind spots where the side view mirrors don’t reveal them. The GLK doesn’t offer a system to reveal objects in the driver's blind spots.
Both the Cayenne and the GLK have standard driver and passenger frontal airbags, front side-impact airbags, head airbags, front and rear seatbelt pretensioners, height adjustable front shoulder belts, plastic fuel tanks, four wheel antilock brakes, traction control and electronic stability systems to prevent skidding.
The Cayenne’s corrosion warranty is 6 years and unlimited miles longer than the GLK’s (10/unlimited vs. 4/50,000).
J.D. Power and Associates’ 2010 Initial Quality Study of new car owners surveyed provide the statistics that show that Porsche vehicles are better in initial quality than Mercedes vehicles. J.D. Power ranks Porsche first in initial quality, above the industry average. With 4 more problems per 100 vehicles, Mercedes is ranked third.
J.D. Power and Associates’ surveys of the owners of three-year-old cars provide the long-term dependability statistics that show that Porsche vehicles are more reliable than Mercedes vehicles. J.D. Power ranks Porsche first in reliability. With 32 more problems per 100 vehicles, Mercedes is ranked 9th.
The Cayenne’s standard 3.6 DOHC V6 produces 32 more horsepower (300 vs. 268) and 37 lbs.-ft. more torque (295 vs. 258) than the GLK’s 3.5 DOHC V6. The Cayenne Hybrid’s standard 3.6 DOHC V6 hybrid produces 112 more horsepower (380 vs. 268) and 169 lbs.-ft. more torque (427 vs. 258) than the GLK’s 3.5 DOHC V6. The Cayenne S’ standard 4.8 DOHC V8 produces 132 more horsepower (400 vs. 268) and 111 lbs.-ft. more torque (369 vs. 258) than the GLK’s 3.5 DOHC V6. The Cayenne Turbo’s standard 4.8 turbo V8 produces 232 more horsepower (500 vs. 268) and 258 lbs.-ft. more torque (516 vs. 258) than the GLK’s 3.5 DOHC V6.
As tested in Motor Trend the Porsche Cayenne is faster than the Mercedes GLK (automatics tested):
Cayenne S |
Cayenne Turbo |
GLK |
|
Zero to 30 MPH |
2 sec |
1.4 sec |
2.2 sec |
Zero to 60 MPH |
5.9 sec |
4.3 sec |
6.8 sec |
Zero to 80 MPH |
9.9 sec |
7.1 sec |
11.5 sec |
Zero to 100 MPH |
14.9 sec |
10.6 sec |
17.9 sec |
Passing 45 to 65 MPH |
3 sec |
2.1 sec |
3.5 sec |
Quarter Mile |
14.4 sec |
12.8 sec |
15.1 sec |
Speed in 1/4 Mile |
98.7 MPH |
108.9 MPH |
91.8 MPH |
On the EPA test cycle the Cayenne Hybrid gets better fuel mileage than the GLK350 4Matic (21 city/25 hwy vs. 16 city/21 hwy).
On the EPA test cycle the Cayenne gets better fuel mileage than the GLK:
Cayenne |
GLK |
|||
2WD |
V6/Auto |
n/a |
16 city/23 hwy |
|
4WD |
V6/Auto |
16 city/23 hwy |
16 city/21 hwy |
|
V8/Auto |
16 city/22 hwy |
n/a |
||
Turbo V8/Auto |
15 city/22 hwy |
n/a |
The Cayenne’s standard fuel tank has 5 gallons more fuel capacity than the GLK (22.4 vs. 17.4 gallons), for longer range between fill-ups. The Cayenne’s optional fuel tank has 9 gallons more fuel capacity than the GLK (26.4 vs. 17.4 gallons).
For better stopping power the Cayenne’s brake rotors are larger than those on the GLK:
Cayenne |
Cayenne Turbo |
GLK |
|
Front Rotors |
13.8 inches |
16.14 inches |
13 inches |
Rear Rotors |
13 inches |
14.57 inches |
11.8 inches |
The Cayenne 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 GLK doesn’t offer ceramic brake rotors.
The Cayenne stops much shorter than the GLK:
Cayenne |
GLK |
||
60 to 0 MPH |
107 feet |
132 feet |
Motor Trend |
For better traction, the Cayenne has larger standard tires than the GLK (255/55R18 vs. 235/50R19). The Cayenne’s optional tires are larger than the largest tires available on the GLK (265/50R19 vs. 235/50R19).
For better ride, handling and brake cooling the Cayenne offers optional 21 inch wheels. The GLK’s largest wheels are only 20 inches.
The Cayenne (except Hybrid) offers active sway bars, which help keep it flat and controlled during cornering, but disconnect at lower speeds to smooth the ride and offer greater off-road suspension articulation. This helps keep the tires glued to the road on-road and off. The GLK doesn’t offer an active sway bar system.
The Cayenne offers an available adjustable active suspension system, which counteracts cornering forces actively, limiting body roll and improving handling and stability. Mercedes doesn’t offer an active suspension on the GLK.
For a smoother ride and more stable handling, the Cayenne’s wheelbase is 5.5 inches longer than on the GLK (114 inches vs. 108.5 inches).
For better handling and stability, the track (width between the wheels) on the Cayenne is 5.1 inches wider in the front and 3.2 inches wider in the rear than on the GLK.
The Cayenne Turbo handles at .95 G’s, while the GLK350 4Matic pulls only .76 G’s of cornering force in a Motor Trend skidpad test.
The Cayenne Turbo executes Motor Trend’s “Figure Eight” maneuver 3.4 seconds quicker than the GLK350 4Matic (24.8 seconds @ .81 average G’s vs. 28.2 seconds @ .59 average G’s).
For greater off-road capability the Cayenne has a greater minimum ground clearance than the GLK (8.7 vs. 7.9 inches), allowing the Cayenne to travel over rougher terrain without being stopped or damaged. The Cayenne Turbo’s minimum ground clearance is 2.85 inches higher than on the GLK (10.75 vs. 7.9 inches).
The Cayenne has .7 inches more front headroom, 3.3 inches more front shoulder room, .9 inches more rear legroom and 1.3 inches more rear shoulder room than the GLK.
For enhanced passenger comfort on long trips the Cayenne’s rear seats recline. The GLK’s rear seats don’t recline.
The Cayenne has a larger cargo area with its rear seat up than the GLK with its rear seat up (23.7 vs. 23.3 cubic feet). The Cayenne has a larger cargo area with its rear seat folded than the GLK with its rear seat folded (62.9 vs. 54.7 cubic feet).
A low lift-over cargo hatch design makes loading and unloading the Cayenne easier. The Cayenne’s cargo hatch lift-over height is 25.5 inches, while the GLK’s liftover is 27.8 inches.
The Cayenne’s cargo area is larger than the GLK’s in every dimension:
Cayenne |
GLK |
|
Length to seat (2nd/1st) |
36.2”/70.7” |
35”/65.9” |
Min Width |
45.5” |
37.4” |
Height |
35.5” |
33” |
The Cayenne’s rear cargo window opens separately from the rest of the liftgate door to allow quicker loading of small packages. The GLK’s rear cargo window doesn’t open.
Unlike the driver-only memory system optional in the GLK, the Cayenne offers an optional driver and passenger memory, so that when drivers switch, the memory setting adjusts the driver’s seat, steering wheel position and outside mirror angle and the front passenger seat also adjusts to the new passenger’s preset preferences.
The Cayenne’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 GLK does not have an oil pressure gauge.
The Cayenne’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 GLK’s standard manually variable intermittent wipers have to be constantly adjusted.
While driving with high-beams on, sensitive light sensors available for the Cayenne detect other vehicles which could be blinded and automatically switch to low-beams. The GLK doesn’t offer automatic dimming high-beams.
The GLK’s optional cornering lamps activate a lamp on the front corner when the turn signal is activated. The Cayenne’s optional adaptive cornering lights turn the actual headlight unit up to several degrees, depending on steering wheel angle and vehicle speed. This lights a significant distance into corners at any speed.
To better shield the driver and front passenger’s vision, the Cayenne has standard dual-element sun visors that can block glare from two directions simultaneously. The GLK doesn’t offer secondary sun visors.
The Cayenne’s optional air conditioned front seats cool the driver and front passenger and help take the sting out of hot leather in Summer. The GLK doesn’t offer air conditioned front seats.
To keep a safe, consistent following distance, the Cayenne 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 GLK doesn’t offer an adaptive cruise control.
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