Mmm Mmm Good

Odd breed, the Japanese midsize premium sedan.

Sophisticated to a fault, often heroically optioned and typically fitted with achingly refined V-6s or V-8s, they are perennial dogs in the market.

Toyota Motor Corp.'s mighty Lexus Div., now moving into the third generation of its GS lineup, has managed nothing more than a surface scratch in the market dominated by Mercedes-Benz's E-Class and BMW's 5-Series, with minor roles played by the Audi A6 and Cadillac's STS.

Ward's data shows the soon-to-be-replaced GS (8,262 U.S. sales last year) is outsold 7-to-1 by the E-Class (58,954) and 5-to-1 (45,584) by the 5-Series.

The fortunes of the two other Japanese mid-luxury sedans, Nissan Motor Co. Ltd.'s Infiniti M series and Honda Motor Co. Ltd.'s Acura RL, demonstrate how quickly the Japanese are moving to fix their bungled efforts.

The RL was redesigned and drastically repositioned as a sport sedan for '05, and immediately edged past the aging Lexus GS to sell 8,753 units last year — a 28% sales boost.

Infiniti, meanwhile, is under way with a totally redesigned M series for '06, and it has the audacity to suggest it will sell 20,000 units annually — 10 times the 2,090 units that found sympathetic homes last year.

Infiniti hasn't lost its mind. Those in charge of the brand are convinced the new M simply is a radically better car. They're mostly correct.

One factor that hurt the outgoing M was that it was a single model: M45, a rear-wheel drive (RWD) sedan with a 4.5L DOHC V-8. The '06 M lineup is just that — a lineup. There now are five models and two engine choices, the 4.5L V-8 for the M45 and M45 Sport, and Nissan's wide-ranging “VQ” 3.5L DOHC V-6 for the M35, M35 Sport and M35x, which features the same all-wheel-drive system used for Infiniti's entry G35 sedan.

More important, the new M35/M45 are the first models from the second generation of the company's lauded FM (front midship) rear-drive platform. The original FM underpins both the G series and FX cross/utility, the two excellent new Infinitis that have supercharged sales at the once-sleepy upscale division.

Make your own decision about the new M's design, which to our eyes advances the successful themes, particularly the sweeping front, Infiniti worked to such good effect with the G35.

In profile, blandness romps from the A-pillar back, and there are a few unnerving Tokyo-limousine insinuations left over from the flaccid Q45 flagship (the last “old guard” Infiniti still on the road), particularly in the semi-pinched, over-detailed tail.

The M35/M45 mostly looks like an elongated, less-interesting G35, so worse things have happened. Just ask BMW.

Japanese sport/luxury styling remains a work in progress. The new M's real story is the sinuous FM chassis, the chesty engines and a tremendously crafted interior that's sure to spend a few long weekends in Audi's teardown shop.

The original FM structure underpins all of Nissan's new RWD/AWD cars and cross-overs, and engineers claim the second-gen FM is vastly improved and 60% new, in-cluding 250 more welds and a 30% boost in torsional rigidity.

On the high-speed 2-lanes of the desert, the new M turns into corners with a sharpness that rivals, to our minds, the current BMW 5-Series. The steering, as with most premium vehicles these days, isn't exactly transmitting messages with Braille-like detail, but it is not bad, either. Body roll and damping — traditional Japanese luxo-sport weak points — are clipped and controlled by the double-wishbone front and multi-link rear independent suspension.

Sport models get 19-in. wheels instead of the standard 18-inchers, and co-conspirators in the M's newfound Germanic road manners are the aluminum hood, decklid and inner/outer door panels that contribute to curb weights that, even with the V-8, wiggle under the 4,000-lb. (1,815-kg) mark. Only the AWD M35x, at 4,004 lbs. (1,817 kg) exceeds two tons.

Even so, the Germans still do it lighter: Mercedes' E500 weighs 3,812 lbs. (1,730 kg) and the aluminum-intensive BMW 545i is 3,814 lbs. (1,731 kg).

The new M's two available powerplants are class-leading. The well-known VQ 3.5L DOHC V-6, in this application, generates 280 hp and 270 lb.-ft. (366 Nm) of torque with the same turbine-like characteristics and peerless noise, vibration and harshness that have made it a benchmark for a decade.

Meanwhile, the 4.5L DOHC V-8, at 335 hp and 340 lb.-ft. (461 Nm), feels more lively than ever. True, its intake and exhaust sounds, while exquisitely refined, are too muted for a “sport” sedan, but there's no denying the V-8 generates serious scoot in almost all speed ranges.

Testimony to the V-6's might is that in many situations it gives up little to the V-8.

In the cabin, Infiniti claims inspiration for the M's spectacular interior came from fine pianos.

There's certainly the perception of a keyboard-like sweep to the entire dash, and Steinway wouldn't turn down the cherry and other woods expertly accenting the center console and upper dash. And the assembly is frankly amazing. In the difficult and openly exposed transitions between wood and plastic pieces in the center dash area, for example, you couldn't wedge an envelope in the seams.

The upper dash, on a semi-horizontal shelf, incorporates Infiniti's version of the driver-machine interface, a much-improved large round knob with a variety of input arrangements.

It helps reduce the sheer number of buttons cluttering the dash, and each successive generation of these systems is more intuitive, with Infiniti's interpretation currently about the best you'll find.

There is a collection of gizmos and gadgets typical for this species, so we'll call out just two.

The “winner” is the no-key entry and ignition system, which uses a transponder that can be kept in a pocket or bag. The driver can lock and unlock the car, as well as start the engine, without handling the transponder.

Nothing new there, but Infiniti's thoughtful and beautifully engineered “dock” for the transponder, centered in the dash to the left of the steering wheel, should be the prototype for all other systems, most of which expect you to toss the transponder in the cupholder if you don't want it in your pocket or bag.

Less value comes from the optional lane-departure warning system. A camera monitors the car's position vis-a-vis the road markings and sounds a beep if you stray from your lane. Inveterate cell-phoners might find it a comforting reminder other vehicles may not be anxious to share their lanes, but for conscientious drivers, it's just something else to beep at you.

Another foible is the standard 5-speed automatic transmission for all M models. It works fine. But it has just five ratios, while the European and U.S. competition have moved on to 6- and 7-speed units.

The Japanese auto makers have been inexplicably slow to adopt multi-cog automatics, and it is uncharacteristic for them to lag in foundation technology. We expect Infiniti and others to right that wrong in quick order.

Finally, what would a new Japanese premium car be without an over-the-top engineering feature? For the new M35/M45, that would be the rear-wheel-steering system that comes only with Sport models.

Rear Active Steer uses an electric motor to alter the angle of attack of the rear suspension's two lower links for each wheel. Engineers say RAS enhances cornering agility and increases stability. It probably does, but as with past attempts at rear-steer, the on-the-road benefits seem esoteric — at least on our one-day test drive.

Overall, however, the RAS-equipped Ms display a flexibility in tight corners that does belie the car's size.

The '06 M35/M45 are dramatically improved and drastically more competitive than the superceded M45, and pricing won't hurt the new-generation car's cause. The M35 starts at $39,900, with the M35x and Sport at $42,000 and change. The M45 base price is an alluring $46,750 and runs to $49,550 for the M45 Sport.

A V-6 Mercedes E320 starts at $48,500, and a V-8 E500 clears the room at $56,800.

Think other Japanese nameplates will be the new Infiniti M's prime competition? Consider that Acura's all-new RL starts at $49,100, which in comparison to the well-equipped and resoundingly powerful M45 appears as vain as Mercedes' pricing, particularly considering the RL is sold only with a V-6.

No wonder, then, that Infiniti projects a modest 1,000% jump in sales for its new M.

'06 Infiniti M45 Sport

Vehicle type: Front-engine, rear-wheel drive, 5-passenger 4-door sedan

Engine: 4.5L (4,494 cc) DOHC V-8, aluminum block/aluminum heads

Power (SAE net): 335 hp @ 6,400 rpm

Torque: 340 lb.-ft. (461 Nm) @ 4,000 rpm

Compression ratio: 10.5:1

Bore × stroke (mm): 93 × 82.7

Transmission: 5-speed automatic

Wheelbase: 114.2 ins. (290 cm)

Overall length: 192.6 ins. (489 cm)

Overall width: 70.8 ins. (180 cm)

Overall height: 59.5 ins. (151 cm)

Curb weight: 3,995 lbs. (1,813 kg)

EPA fuel economy, city/highway (mpg): 17/23

Market competition: Acura RL; Audi A6; BMW 5-Series; Cadillac STS; Lexus GS; Mercedes-Benz E-Class; Volvo S80