2008 Mercedes-Benz GL-Class Trims and Specs

The refined 3.0-liter, turbocharged V6 diesel engine that powers the 2008 Mercedes Benz GL320 CDI operates relatively quietly and doesn't produce the fumes that sometimes trouble older diesels, drivers and reviewers note. In fact, many drivers will barely notice that a diesel hides under the hood, instead of a typical gas-powered engine.

For the most part, the diesel V6, which produces 215 horsepower, capably powers the full-size GL320 SUV, which tips the scales at just over 5,300 pounds. However, acceleration isn't great, drivers note. On the positive side, the diesel V6 excels in fuel efficiency, getting as much as 24 miles per gallon at highway speeds.

While the CDI (common-rail injection) diesel runs on ultra-low-sulfur diesel fuel, which helps lower emissions, the 2008 GL320 CDI has not been approved for sale in the states of California, Connecticut, Maine, Massachusetts, New York, Pennsylvania, Rhode Island, and Vermont.

Outside, the 2008 GL320 CDI displays a fluid, aerodynamic exterior appearance, with a silver grille, light-sensing headlights, dual square stainless-steel exhaust tips, and a sunroof with a retractable sunshade. Inside, the big SUV comes equipped with multifunction steering wheel, power-adjustable heated front seats, a leather-wrapped steering wheel, brown bird's-eye maple wood trim, and dual-zone climate control.

The GL320 CDI also comes standard with 4MATIC all-wheel drive, four-wheel electronic traction control, an Electronic Stability Program, a seven-speed automatic transmission, antilock brakes, and a four-wheel air suspension, which automatically adjusts depending on passenger and cargo weight.

Drivers and reviewers note that the full-size SUV can often seem too big in small spaces like tight parking lots. However, it comfortably seats seven passengers in three rows, and with the second- and third-row seats folded down, it provides more than 83 cubic feet of cargo space.

The Mercedes-Benz GL450 changes little for 2008, but it still offers many top-notch features that make it a competitive choice for drivers seeking a well-equipped full-size SUV. Underneath its sleek, sculpted exterior, the GL450 features unibody construction, which results in better handling, a smoother ride, and an overall lighter weight, according to Mercedes-Benz. Still, the GL450 weighs in at just under 5,300 pounds, so while the big SUV accelerates at a steady pace (0 to 60 in 7.4 seconds), it won't break any speed records.

Speed's not the point here, of course, and in other measures, such as passenger space, cargo space, safety features, and off-road capability, the GL450 excels. The big SUV comes equipped with 4MATIC all-wheel drive, which continuously monitors the speed of all four wheels and reduces power or applies brakes as needed when it detects wheel slippage. Four-wheel electronic traction control, an Electronic Stability Program, antilock brakes, and a four-wheel air suspension, which automatically balances the suspension depending on passenger and cargo weight, also come standard.

A 335-horsepower, 4.6-liter V8 engine powers the GL450. The engine links to a seven-speed automatic transmission with a column shifter. Using rocker buttons on the steering wheel, drivers can access the transmission's Touch Shift feature, which enables manual shifting.

The GL450 seats seven passengers in three rows of seating. With the second- and third-row seats folded flat, the GL450 provides more than 83 cubic feet of cargo space. And when even bigger loads need moving, the big SUV can tow up to 7,500 pounds.

Standard features for the 2008 GL450 include a sunroof with a retractable sunshade, a multifunction steering wheel, power-adjustable heated front seats, a leather-wrapped steering wheel, and brown bird's-eye maple wood trim. The eight-speaker audio system includes a six-disc CD changer mounted in the glovebox.

Other features include Downhill Speed Regulation, which manages the throttle and brakes to ensure safe driving on steep slopes, and Hill Assist, which prevents rollback when the driver switches between the brake and gas pedals on steep uphill or downhill grades.

Options include an Off-Road Package, which includes center and rear locking differentials, a two-speed transfer case, skid plates with underride protection, and a dynamic compass display.

New for 2008, the Mercedes-Benz GL550 replaces the GL500 in the automaker's lineup, and as the numerical part of its name implies, it receives a bump in power, making it the new top dog in the GL-Class lineup. The GL550 also sports a number of exterior design upgrades that distinguish it from its stablemates in the GL-Class.

A new 382-horsepower, 5.5-liter V8 engine powers the GL550. It's the same engine that drives other high-end Mercedes vehicles, including the E550 sedan, the CL550 coupe, and the S550 sedan. The V8 engine links to a seven-speed automatic transmission, which has been geared to ensure quick, smooth acceleration. The transmission includes the Touch Shift feature, which enables the driver to upshift and downshift manually using rocker buttons located behind the steering-wheel spokes.

Updated exterior features include a deeper chrome grille, a new front bumper design, chrome roof rails, dual chrome exhaust tips, and a power liftgate. Underneath the sleek exterior, the GL550 features a unibody construction, which results in better handling and a smoother ride, according to Mercedes-Benz.

Overall, the GL550 comes with the most extensive list of standard features of any Mercedes SUV. Features include leather upholstery and trim, power-adjustable heated front seats, heated rear seats, a wood-and-leather multifunction steering wheel, Burl Walnut wood trim, and an 11-speaker Harman Kardon digital audio system with a six-disc CD changer located in the glovebox.

Like all SUVs in the GL-Class, the GL550 comes equipped with 4MATIC all-wheel drive, which continuously monitors the speed of all four wheels and reduces power or applies brakes as needed when it detects wheel slippage. Four-wheel electronic traction control, an Electronic Stability Program, antilock brakes, and a four-wheel air suspension, which automatically balances the suspension depending on passenger and cargo weight, are also standard.

Other features include Downhill Speed Regulation, which manages the throttle and brakes to ensure safe driving on steep slopes, and Hill Assist, which prevents rollback when the driver switches between the brake and gas pedals on steep uphill or downhill grades.