On the positive side, the GL450's stereo can be used to play various kinds of digital audio, including MP3 and WMA discs. With such compressed audio formats playing, the LCD in the center of the dash displays information for the current track playing, but there doesn't appear to be any way to call up all the ID3 tag information associated with a specific disc (such as artist, folder, album, and so on).
Our 2007 Mercedes-Benz GL450 test car came with the $4,500 Premium I option package, which equipped it with a power tailgate, a Parktronic radar-based parking aid, a DVD navigation system, autodimming/power-folding mirrors, power steering, a memory system for the front seats, and a six-month Sirius Satellite Radio subscription. Parktronic is a very useful feature in a car of this size, and we especially like the cowl- and rear-deck-mounted LED clusters, which gives a visual indication of how near the car's front two front fenders and rear bumper are to obstacles: as proximity to an obstacle decreases, more lights illuminate, with the sixth and seventh red lights accompanied by a warning beep. The optional rearview camera ($500) was also handy in helping us get in and out of tight spots. Other impressive standard safety equipment on the 2007 Mercedes-Benz GL450 includes second-row seat-mounted air bags, window curtain air bags for all three rows, and active front head restraints.
Additional options on our test car included a tri-zone climate control system ($1,320), which adds a rear climate zone and six extra vents around the cabin, as well as a glass sunroof package ($1,500), which includes a glass sunroof and power-rear three-quarter windows.
Like the E550 and the S550, the Mercedes-Benz GL450 does come with the option of hands-free calling. However, those who want to connect their phones by the standard Bluetooth hands-free profile (rather than via Mercedes' proprietary MHI interface) have to fork out $408 for the pleasure of a separate module, another black mark against the GL450's cabin tech.
Under the hood
Before we go under the hood, the Mercedes Benz GL450's hood itself gives some indication as to its performance aspirations. With a power bulge and two air vents identical to those on the SL550, the mammoth SUV seems to wish it had been born as something toward the sportier end of the Mercedes lineup. With its 335-horsepower 4.6-liter V-8 engine, adaptive suspension, and steering-wheel-mounted paddle shifters, the GL450 does have the soul of a sports car, but that is somewhat dampened by its 5,249-pound curb weight. Nevertheless, this is one permanent four-wheel drive SUV that can pull its own weight: with the gears held into higher rev bands in manual-shift mode, the GL450 barrels forward with the swiftness of a much smaller car. In addition to its load-leveling capabilities, the air suspension can be configured in a number of ways to accommodate different terrains and driving styles.
Our test car came equipped with the $2,200 off-road package, which endowed it with an Adaptive Damping System (ADS), enabling drivers to adjust the ride height of the vehicle using a rotary dial in the central column to accommodate a variety of driving speeds: Off-road 3 mode raises the vehicle's body a full 4.3 inches from its default (highway) height and can only be used up to a maximum speed of 20mph. Three other settings include Off-road 2 (body raised 3.1 inches, max speed 40mph); Off-road 1 (body raised 1.2 inches, max speed 60mph); and High-speed (body lowered 0.6 inch). The ADS will lower the car itself when highway speeds are reached. Also part of the off-road package, the GL450 also comes with two locking differentials for those who really want to maculate their $70K Benz through mud, water, or deep snow.
Another standard performance feature on the GL450 is its adjustable suspension, which, in addition to the default suspension configuration, gives drivers the option of setting the suspension to Sport or Comfort mode. Driving around town, we noticed a demonstrable difference between the two settings: In Sport mode the tuning is surprisingly stiff with imperfections and bumps in the road translating into the cabin, and a more surefooted feeling in cornering. In Comfort mode--far more suited to the GL450's luxobarge persona--rough pavement is effectively damped out, leading to a very soft, lolloping ride. Other notable performance features of the Mercedes-Benz GL450 include its Downhill Speed Regulator (DSR), which can be set at speeds of up to 10mph to prevent the car running away on inclines; and a hill-start assist, which holds the car stationary for a few seconds to allow drivers to get their loafer from the brake to the gas pedal.
Like the 2007 Mercedes S550, the GL450 does come with the option of Distronic adaptive cruise control, which allows drivers to set a constant distance between the front of the car and the back of the car ahead when driving on the freeway; however, our tester was not so equipped.
In our week with the GL450, we observed an average gas mileage of 15.3mpg, right in the middle of the EPA estimates of 14mpg city and 18mpg highway, but disappointing for any new car, especially one with a seven-speed automatic gearbox.
The 2007 Mercedes-Benz GL450 comes at a base price of $54,900, but the price tag for our tester was supplemented by a litany of options: $4,500 for the Premium I package (DVD navigation system, Sirius Satellite Radio, Parktronic, auto-dimming power-folding mirrors, power steering, and a memory system for the front seats); $2,650 for the rear-seat entertainment system; $2,200 for the enhanced off-road package (Adaptive Damping System, two locking differentials); $1,500 for the sunroof; $1,500 for macadamia leather appointments; $1,320 for the tri-zone climate control; $900 for the lighting package (curve-illuminating Bi-xenon headlights, front fog lights); $700 for a Desert Silver paint job; $540 for the wood-and-leather steering wheel; $500 for the rearview camera; and $150 for ambient interior lighting. Oh, and don't forget the $775 destination charge. All told, our tester carried a hefty price tag of $72,135.