The full-size S-Class sedans from Mercedes-Benz are getting a bit long in the tooth -- a successor model is due to be unveiled this fall at the Frankfurt show -- but the big four-door remains a formidable presence in the luxury market in terms of size, comfort, safety and advanced technology.

We tested a 2005 S430 4Matic with all-wheel drive (a no-cost option) and a sticker of $79,430.

SHE: I noticed the salon where you've been getting your hair cut lately is looking for a "nail technician." But that's only half the battle. What they also need is a chair just like the front seats in the S430. They're so plush and loaded with gizmos, including power adjustable lumbar support, they remind me of the fancy pedicure chairs at high-end spas. I loved that gathered nappa leather, which is an $840 option. And we didn't even have the uber-seats with the active ventilation and massage features. But the car's exterior design -- not stylish at all! I'd call it almost frumpy.

HE: Gee, I guess you nailed it. The S-Class has never been a car for younger drivers. Mercedes likes to promote it as the perfect status vehicle for those who have "arrived." So there traditionally has been more emphasis on the interior than the exterior. Nor is this really a driver's car, a role that falls more on the shoulders of the BMW 7 Series in this price segment. The S-Class is more about the ride quality, which is pretty smooth and buttery, thanks to the air suspension and automatic damping. If you hadn't spotted the 4Matic badge on the decklid, you'd be hard-pressed to tell this is a four-wheel-drive vehicle because the S430 delivers a real luxury-car ride. It's more about comfort than precise control, which is not a strong suit. In fact, driving the S430 is a little like piloting a cruise ship; you sort of point it in the direction you'd like to go, and it generally follows without too much protest.

SHE: That might be overstating the case. I didn't find steering the S430 to be any more of a challenge than driving a big domestic model, like a Cadillac DTS or a Lincoln Town Car. It does have a surprising amount of power from the 4.3-liter V-8, which makes 275 horsepower and 295 pounds-feet of torque. Mercedes has matched the V-8 with a five-speed Tiptronic automatic, which you can shift like a manual, but the car isn't really conducive to that because it feels so big and heavy. I guess "ponderous" would be the word that comes to mind. Be forewarned, too, that the powerful V-8 and the S430's massive curb weight of 4,390 pounds extract a stiff penalty in terms of fuel economy -- so stiff that you have to pay a federal gas-guzzler tax of $1,000 up front when you buy the car. And with EPA ratings of 17/22, you might as well be driving a big SUV.

HE: There are certainly trade-offs. You have lots of power available under your right foot, but like many of the Mercedes products we've driven, there is a noticeable and annoying throttle lag when you're trying to kick the transmission down and get extra power for passing. On the other hand, this lives up to Mercedes tradition in providing an amazing complement of safety equipment, including full side air bags and side cushions, as well as BabySmart seats, antilock brakes, electronic stability program and the company's fabulous PRE-SAFE system that anticipates an impending collision and puts the vehicle's safety systems on red alert.

SHE: I like Mercedes' version of OnStar, which they call TeleAid, although when we tested it, it took the remote operator about 10 rings to answer a call. So I suppose you're right about trade-offs. Like the trunk, which is cavernous and comes with neat features like a cargo net and built-in Velcro straps for securing smaller items. But where's the split folding rear seat for stowing longer stuff? The power trunk lid has a cool disappearing handle and pulls itself shut, but it flies open awfully quickly, too; I almost clunked my jaw on it. But I was impressed by some of the attention to detail inside the car, especially in the roomy rear compartment. The back seat has individual vanity mirrors, reading lights, vents and cup holders.

HE: The S430 is not for everyone. I think its chief appeal probably lies with older, more affluent customers looking for adequate power, lots of features and just a little more status than they'd get with a Cadillac or a Lincoln.

He drove, she drove Anita and Paul Lienert are partners in Lienert & Lienert, an Ann Arbor-based automotive information services company.

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2005 Mercedes-Benz S430 4Matic

Type: Front-engine, all-wheel drive, five-passenger sedan.

Price: Base, $77,020 (inc. $720 destination charge and $1,000 gas-guzzler tax); as tested, $79,430.

Engine: 4.3-liter V-8; 275-hp; 295 lb-ft torque.

EPA fuel economy: 17 mpg city/22 mpg highway.

Where built: Germany.

Key competitors: Acura RL, Audi A8, BMW 750Li, Cadillac DTS, Cadillac STS, Infiniti Q45, Jaguar XJ, Lexus LS 430, Lincoln Town Car, Maserati Quattroporte, Mercedes-Benz CLS500, Volvo S80.

12-month insurance cost, according to AAA Michigan: $1,936. (Estimate. Rates may be higher or lower, depending on coverage and driving record.)

Anita's rating: 4

Likes: Front seats look like they came from a high-end spa. All-wheel drive at no extra charge. Powerful V-8 engine. Roomy rear compartment with many amenities. Great warranty package. Love the built-in Velcro straps in the trunk to secure smaller items. Beautiful chrome thresholds on all four doors.

Dislikes: Exterior design is frumpy. At nearly $80,000, one of the most expensive luxury sedans in the class. $1,000 gas-guzzler tax.

Paul's rating: 4

Likes: Comfort in spades. Air suspension, adjustable damping make for buttery ride. Terrific safety features, including full air-bag protection, stability program and more. Gorgeous wood trim in cabin.

Dislikes: Handles more like a cruise ship than a sports car. Noticeable throttle lag when transmission kicks down. CD changer is virtually inaccessible in the trunk. Navigation/audio system requires too much attention from driver.

Rating system

1. Unacceptable, 2. Subpar, 3. Acceptable, 4. Above average, 5. World class