The flagship of the fleet should be fashioned from an uncommon and uncompromised blend of technology and opulence. It should sport elements that distinguish it from the lesser vessels of the line, instill in its occupants an aura of invincibility and convey to the driver a lofty level of dynamic excellence, tempered but not tamed by a lush layer of luxury.

Does the 2007 Lexus LS 460, flagship of Toyota's youthful premium franchise, live up to these criteria? Yes. Is the LS 460 the equal of such grandees of the high-end game as the Mercedes-Benz S-Class and BMW 7 Series? After a week in this standard-wheelbase example, our answer is, "Not yet."

A two-tiered model line
For the first time, the LS is offered in two versions. The standard LS 460 ($61,000) is just over a half-inch longer overall than the outgoing LS 430, but its wheelbase is 1.8 inches longer and both tracks are 1.5 inches wider. The extended-wheelbase LS 460L ($71,000) adds 4.7 inches in length over the LS 460 with an equal increase in wheelbase. To maintain styling equilibrium between the two new models, the front and rear overhang dimensions are identical.

The LS 460's 198-inch overall length falls halfway between the Mercedes-Benz E-Class' 191 inches and the S-Class' 205 inches. At 4244 pounds, the Lexus is no lightweight, but it does beat the aluminum-rich Audi A8 by about 44 pounds. The S550 and 745i each weigh about 220 pounds more.

Our Mercury Metallic tester was well optioned, which kicked up the sticker to more than $72,000, a hefty sum that could have been lowered by $5,645 through elimination of the navigation system and Mark Levinson Reference Surround Audio system. However, the car did not include several notable options, including the Advanced Parking Guidance System — which basically parks the car for you — or Lexus' new Pre-Collision System with Dynamic Radar Cruise Control, which senses a possible front collision and prepares the car accordingly. Nor did it have the air suspension, which is only available on the LS 460L.

First in the race to 8x8
Both LS models share a single drivetrain: a new 4.6-liter V8 with all the electronic gizmos imaginable, and it sends power to the rear wheels through a world-first eight-speed automatic transmission.

It's the world's first combination of eight-cylinder engine and eight-speed transmission, and it was worth the wait. Aided by such engine-uity as the world's first electrically controlled valve timing system, dual injection and an electronically controlled induction system, the 460's sophisticated engine is as smooth as Swiss chocolate melting in the sun. Its 380 horsepower is a 102-hp bump over the previous 4.3-liter V8's output, and the 367 pound-feet of torque is a 55 lb-ft increase in twist.

Equally state-of-the-art is the transmission. A new hydraulic control system utilizes four disc clutches for ultrasmooth gear transitions, and a torque converter with variable control helps low- and midrange torque and delivers better fuel economy. The driver can choose to shift manually or drop it into "S" mode, which defaults to gear choices from 4th through 7th. Every mode is effortless to initiate, and it all works smoothly enough, but we would have preferred a little spark in performance when we were manually shifting through the gears. At the test track we tried both automatic and manual gearbox modes, but found the performance to be equivalent with either shift input.

Our test car accelerated from zero to 60 mph in 5.8 seconds, an admirable figure but slower than the 5.4 seconds claimed by the factory. We couldn't match the claimed quarter-mile time of 13.8 seconds either — 14.2 seconds was our best run.

Far more important was the V8's utter lack of obvious effort, even when it was recording performance numbers on par with the larger V8 of the Mercedes-Benz. So seamlessly and effortlessly is the power delivered, however, that putting the pedal down is about as thrilling as watching the Golf Channel. On the upside, the power boost is accompanied by class-leading fuel mileage ratings of 19 city/27 highway. We recorded a best of 25 mpg out of three tanks of fuel.

Floaty, but still quick and controlled
To help reduce unsprung weight, aluminum was used extensively throughout the suspension. Up front is a new upper and lower wishbone setup with coil-over monotube shocks and a hollow stabilizer bar, while out back the multilink suspension carried over from the previous LS has had its mass reduced and settings firmed up for better ride and handling. Coil-overs and a stabilizer bar are also part of the package.

Our biggest beef with the LS 460 is that the suspension is tuned too softly and doesn't sufficiently stifle the excessive nose dive during braking and body lean through hard corners. Plus, it doesn't do particularly well damping the concrete freeway jiggle that occurs over expansion joints. The competition seems to have figured out how to combine crisp body control with a supple ride.

After a flurry of complaints about the too-intrusive vehicle stability system in some of its vehicles, Lexus responded by fitting the LS 460 with a switch that allows the system to be completely turned off. This allowed us to really explore the handling limits of this big sedan, and we left the test track impressed. Its 0.82g skid pad and 63-mph slalom number are average at best, but it's well-balanced for a car this size. It's big and it rolls a lot, but it sticks pretty well and the fundamentals required to control it at the limit are intuitive.

The other dynamic element that troubled us was the LS 460's brakes. In stop-and-go traffic, the electronically controlled four-wheel discs are grabby and abrupt and inserted a slight hiccup into an otherwise suave progression down the road. We didn't dislike them nearly as much during our tests, however, when they exhibited negligible fade and short stopping distances. From 60 mph the Lexus stops in just 128 feet, which is almost as short as the Mercedes S550.

A more sophisticated system is available with the optional Touring Package, which includes larger spiral-fin ventilated rotors, high-friction brake pads, four-piston aluminum calipers in front and two-piston aluminum calipers in the rear. We're eager to experience those bigger binders.

Luxury condo living, on wheels
If there's a faultless aspect of the LS 460, it's the interior. In an ergonomic sense, the cockpit's layout is perfection. There's no great learning curve required to operate the climate controls, audio system and other features, and the Optitron electroluminescent gauges are especially handsome in design and effective visual messengers. The front seats are so fully adjustable — 16 ways — that any humanoid species would have no trouble dialing in a comfortable position, and those in the rear needn't suffer either.

Ordering up the Comfort Package buys climate-controlled front seats, heated rear seats, a heated steering wheel and a power rear window sunshade, while the Comfort Plus Package adds power reclining rear seats and headrests, climate-controlled front and rear seats and rear seat-mounted side airbags. This $3,620 option brought our test car's airbag total up to 10, two more than Lexus' class-leading eight standard bags. (With the Executive Class Seating Package in the 460L, the number of airbags is 11.) The front-passenger and knee bags are dual-stage, and the passenger's bag also is twin-chambered to reduce facial/cranial contact with the expanding bag.

The interior is just as brilliant in an aesthetic sense. Grain-matched wood trim — available in medium brown walnut, dark gray bird's eye maple and dark brown ash — is complemented by standard perforated leather upholstery, offered in alabaster white, cashmere or light gray. From the exquisite stitching in the leather to the matching of the wood grain, the fit and finish is without peer. For example, the wood trim on the steering wheel is provided by Tendo, a high-end furniture studio.

We're less taken, however, with the sedan's overall exterior design, which seems so calculatedly derivative of other recent Lexus designs that its singular dynamic qualities seem subjugated by the family resemblance. There's too much BMW 7 Series in the shape as well.

It's all in the driving, or is it?
To quote the chief designer of the Lexus LS 460, Yo Hiruta: "The ratio of design cost to total car cost is higher for Lexus than for other cars."

You could have fooled us. Perhaps we're being too harsh, but assessing the new Lexus LS 460 in light of Mr. Hiruta's statement does lend some clarity to our ambivalence about this fourth generation of Lexus' flagship sedan. It's a car we deeply respect and admire, but it's not one that has swept us off our feet. While we value its comfort, impeccable build quality and expected reliability, what we love most about cars is driving them, and the LS 460 falls just short of delivering the snappy, precise control of the road we covet most. If we were somehow penalized to give up our driver license, we can think of few other cars in which we'd rather be the passenger.

Still, despite some areas we feel could use some improvement — a too-soft suspension, grabby brakes, uninspired styling — there is no disputing the LS 460's rightful place at the head of the Lexus fleet.