Not all full-size luxury SUV shoppers are looking to show off their ride to the envious masses on some trendy, club-ridden strip of road. Many are, but plenty are just searching for a vehicle with a plush interior, room for seven, a powerful engine and prestigious image that doesn't require 22-inch rims and twin subwoofers the size of a Barcalounger. For these more rational shoppers, the 2008 Mercedes-Benz GL-Class is the best of the bunch.

Introduced last year, the GL450 and diesel-powered GL320 CDI took home Edmunds.com's Editors' Most Wanted award for SUVs priced above $45,000. With its attractive blend of passenger space, cargo capacity, capable on- and off-road performance and plenty of attractive features at a reasonable price, the GL set itself apart from full-sizers like the Cadillac Escalade and Lincoln Navigator. We were also impressed by the GL450's powerful 4.6-liter V8, which delivered quick acceleration times that bettered the competition.

For 2008, a new trim level, the GL550, arrives. Powered by the same engine that resides in Mercedes' flagship S550 sedan, the new range-topping GL has the power to nip at the heels of more sporting luxury utes like the Range Rover Supercharged and BMW X5 4.8i while still seating six adults in comfort. Stuffed full of all the GL450's optional packages, the 550's price climbs to almost $80,000 -- a very exclusive club indeed. For that price, though, buyers at least get some visual distinction with fender flares, 21-inch AMG wheels and a revised front fascia with a bigger grille and a three-pointed star so large it practically screams, "Achtung! Ich bin ein Mercedes!"

The most intriguing model in the GL-Class line is the GL320 CDI. The letters refer to the turbocharged, 3.0-liter diesel engine under its hood, which like other diesel-powered vehicles, provides massive low-end response and superior fuel mileage versus its gasoline counterparts. The 320 isn't nearly as quick as the GL450, but it's strong around town and powerful enough for most families. Plus, it's $2,500 cheaper than the identically equipped 450 and its 26.4-gallon fuel tank results in a 700-mile range. Of course, bad thoughts linger from the clattering, smoky oil-burners from the 1970s and '80s, but today's diesels are quiet, not the least bit stinky and very clean. Not quite clean enough for the GL320 to meet the incredibly strict emissions standards of California and the Northeast, but 2009's GL-Class Bluetec diesel will be 50-state certified.

In the rarefied, often ostentatious, air of large luxury SUVs, the 2008 Mercedes-Benz GL-Class manages to present itself with a touch of class. Its mechanical sophistication, unit-body construction and superior craftsmanship also set it apart from other seven-passenger full-sizers, while the 450 and 320 CDI ring in at a price that undercuts a similarly equipped Escalade and other models in the segment. Plus, with available 21-inch wheels, Logic7 sound system and Mercedes' street cred, the GL will still work out just fine for those who want to do plenty of club cruisin'.

The 2008 Mercedes-Benz GL-Class is a large luxury SUV available in three models that each seat seven passengers. The GL450 and GL320 CDI are equipped identically, save for their powertrains. Standard equipment includes 18-inch wheels, "MB-Tex" cloth upholstery, a leather-wrapped steering wheel, dual-zone automatic climate control, power front seats with heat, a power split-folding third-row seat, the COMAND electronics interface and an eight-speaker audio system with glovebox-mounted six-CD changer and auxiliary audio input.

The pricey Premium I Package includes front seat memory functions, a power steering column, a power liftgate, a sunroof, a navigation system with a rearview camera, parking sensors and a Harman Kardon Logic7 sound system with satellite radio. The Premium II Package includes all of the Premium I equipment, plus three-zone climate control (also available as a stand-alone option), rear air-conditioning and adaptive bi-xenon headlamps. The Heating Package adds a heated steering wheel and rear seats, while the Full-Leather Package upgrades the already well-crafted interior.

The GL550 includes all of the above equipment as standard and adds 21-inch wheels and unique exterior styling details. Stand-alone options on the GL450 and GL320 CDI include adaptive cruise control and keyless ignition, while all GL-Class models can be equipped with a rear-seat DVD entertainment system and an iPod integration kit. The Enhanced Off-Road Package is available on the GL450 only.

Each model within the GL-Class has its own engine, but all come with a seven-speed automatic and 4Matic all-wheel drive. The GL450 is powered by a 4.7-liter V8 that makes 335 hp and 339 pound-feet of torque. When fitted with the optional Enhanced Off-Road Package, the GL450 gains center and rear locking differentials, a two-speed transfer case with low-range gearing, and underbody skid plates.

In performance testing, we found the GL450 capable of hitting 60 mph in a quick 6.7 seconds. EPA fuel economy estimates for 2008 are 13 mpg city/18 mpg highway. The GL320 CDI is powered by a 3.0-liter turbodiesel V6. Like all diesels, horsepower is low and torque is high, with 215 hp and 398 lb-ft of torque. Diesels also tend to get better fuel economy, and the GL320 gets an impressive 18/24 mpg rating. Because of their more stringent emissions standards, the GL320 CDI is not sold in several states, including California, New York and Vermont.

The GL550 is powered by a 5.5-liter V8 that produces 382 hp and 391 lb-ft of torque.

Standard safety features on the 2008 Mercedes-Benz GL-Class include stability control, antilock brakes, whiplash-reducing front headrests, first- and second-row side airbags and full-length side curtain airbags with an integrated rollover sensor. Hill start assist, hill-descent control and TeleAid are also included. Buyers of the GL450 and GL320 CDI wanting a rearview camera, and front and rear parking sensors should note that they are only available as part of the Premium Package. These items are standard on the GL550.

Even with its 4.7-liter V8, the Mercedes-Benz GL450 was the muscle car of its class -- and the new GL550 raises the bar even higher. Either gasoline-V8-powered GL is quicker to 60 mph than any other large SUV we've tested, including the Audi Q7 4.2 and Cadillac Escalade. The large Benz is also quiet on the highway, with minimal wind and road noise. Although the diesel GL320 CDI isn't going to break any acceleration records, passing and merging maneuvers come easily, as the seven-speed automatic transmission does an exemplary job of keeping the engine in the meat of its power band. In addition, the GL320's V6 is so quiet and refined you're scarcely aware it's actually a diesel.

Some drivers might find the Mercedes GL's handling to be a bit wallowy -- this isn't a truck you toss around for the sheer joy of it. But the ride and handling compromise is acceptable, and the GL's steering, although a bit slow, is nicely weighted and never numb.

The GL's cabin is well-appointed and a comfortable place to be. Fit and finish is as it should be, seat comfort is exceptional, and headroom and legroom are ample for most positions. The second row could benefit from being able to move fore and aft, as it can get tight with taller occupants seated up front. Nice touches include a one-touch up and down function for all four windows and flush-folding rear headrests to improve the driver's rearward vision (an innovation missing on Benz's R-Class). Third-row access is also well thought out. With the second- and third-row seats lowered, 83 cubic feet of cargo volume is available, which is much smaller than full-size luxury SUVs like the Cadillac Escalade but on par with vehicles like the Acura MDX.