Boston.com's view

MCCALL, Idaho – Think of the 2008 Mercedes-Benz ML550 and GL550 SUVs as purebred pets. One would be a swift Greyhound, the other would be a black lab – larger, but still able to scramble over tough terrain at an owner’s command.

“Luxury SUVs have been fundamental for our growth and success in the US,” Bernhard Glaser, Mercedes-Benz’s general manager of product development, said at the introduction of these models here recently.

The folks at Porsche will tell you the same thing, given that the rise of the Cayenne SUV likely allowed it to remain an independent auto company.

Mercedes entered the SUV market in 1997 with its M-Class. The line now includes four classes of SUVs with a dozen models, from basic to hot rod AMG models. A smaller, entry-level SUV, dubbed the GLK will be officially unveiled this fall. It is meant to compete with the BMW X3, Land Rover LR2, and Acura RDX. The new cars are part of a bid to top last year’s showing, when nearly 30 percent of Mercedes-Benz’s 250,000 sales in the United States were SUVs.

Today, before you could leapfrog all the way to AMG, you’d have to hurdle the powerful new ML and GL models that feature these new 5.5-liter models with engines with a whisper-quiet 382 horsepower and 391 lb.-ft. of torque.

The ML is the smaller of the two and its styling is distinctive, with hints of AMG tossed in. Mainly, the front bumper, with its massive air intake, is the sport feature taken from the AMG stylebook. The grille – which sets this one apart from other Benzes – features a myriad of cubes that smartly pock what would otherwise be a familiar slatted grille. Also distinctive are square, imbedded dual exhausts, with those on the GL bisected by vertical separators for a quad look. Naturally, the big Mercedes star is featured at its center.

Mercedes, in tuning its lineup, has decided that haggling at dealerships over options is a pain. In the past, that could run into crazy prices. Therefore, options on these new models are few, and a formidable array of standard gear includes running boards, sunroof, roof rails (on the GL), a full load of eight airbags – front, side, and above, front to rear – stability control, antiroll sensors, an adaptive seven-speed transmission, navigation, a backup camera, and AMG’s 19-inch spoked wheels on the ML and 21-inch wheels on the GL.

This, of course, adds up to a high base price, though Mercedes states that the added standard gear, even with a higher base, amounts to a 6 percent price cut over last year’s comparable models from last year, which did not have 5.5-liter engines.

Given that the main options are a keyless-go system, a trailer hitch, rear-seat DVD, and a no-cost option to swap the leather-and-wood steering wheel for a heated one, haggling should be minimized – though the customer must walk through the door ready to pay a base of $53,175 for the ML and $77,750 for the GL.

“Keeping it simple for our customers also makes it simpler for our dealers,” said Geoff Day, the company’s director of communications.

So we’ve got the gear, power, and two distinct SUVs (Mercedes doesn’t pretend that either is a “crossover”).

As expected, the ML550, running twisting roads in Idaho’s river valleys, and climbing and descending long mountainous stretches is the spunkier of the two models. In soft and normal suspension settings, the front steering feels a bit light, making the rear feel slightly heavy. But snap it into sport mode and the stiffening of suspension and changes in gearing make it much more diligent.

The GL550 feels solid all-around, evenly weighted. But it’s a bigger rig, with three rows of seats, so that’s to be expected.

Both vehicles had a small “dead” spot at the center of steering (that’s a side to side numbness of about an inch turning from a straight-up wheel). But as I considered this later, I had to remind myself that, luxurious, powerful, and technologically advanced as these vehicles are, they are still SUVs. That means while they ride lower and safer than some earlier SUVs, it’s still a fairly high ride that’s not intended for sports-car-tight steering.

The seven-speed transmission, smooth as silk, has Mercedes leading the pack. The incredibly quiet interior lets you forget you are in an SUV, as does the elegance of leather, wood, metal trim, boffo sound, and other amenities.

The bar keeps going up in the high-end SUV market, and these cars, riding just below models like the AMGs and Porsche Turbo Cayennes, lets you drive close to high performance while packing more power than you are ever likely to use on a public road.

Royal Ford can be reached at ford@globe.com.