Lexus nailed the powertrain competition, but lost significant ground when it came to the rest of the hardware package. The car doesn’t come together as a sum of its parts, and offers a disjointed driving experience that is likely to please only the least demanding owners. Meanwhile, the capable Acura RL was limited mainly by its tires and excess body roll, while the stunning Infiniti M35x proved the equal of Germany’s best.

3rd Place – Lexus GS 300 AWD
In terms of its suspension, brakes, steering, and tires, the 2006 Lexus GS 300 AWD sticks to convention when it comes to our three Asian luxury sedans. It’s got double wishbone suspension design up front, with a multi-link rear and stabilizer bars at both ends. Four-wheel vented discs with ABS, EBD, and brake assist handle stopping chores, while electronically-controlled, vehicle speed-sensing rack-and-pinion steering guides P225/50 Dunlop SP Sport 5000 all-season tires mounted to 17-inch wheels. But the differences that landed the Lexus in third-place were its standard run-flat rubber, buzz-killing stability control system, and brake-by-wire binders.

Run-flat tires have a stiffer sidewall than regular tires, which allows them to be used for short periods of time even when they have no air pressure inside. But that stiff sidewall produces a hard ride, and the Lexus GS 300 AWD suffers plenty of impact harshness. And despite the best efforts of the well-tuned suspension, the ride quality is, as one editor said, “busy and jittery, like the tires are over-inflated.”

Not only did the run-flats produce a less pleasing ride quality, but grip was down, too. With the narrowest section width and both a taller profile and smaller wheel diameter than the best-in-test Infiniti, the GS 300 AWD’s handling was described as “sloppy, sloppy, sloppy” by one driver. Seems part of the trouble lay with the Lexus VDIM electronics management system, which handles the GS 300 AWD’s stability control, and which cannot be turned off. Everyone complained that it stepped in just as the real fun was getting started, but the reality is that typical drivers using public roads will find the Lexus’ performance envelope to be wider than they’ll ever wish to use. As one staffer put it: “The Lexus delivers 7/10ths entertainment value.” And that’s going to be good enough for most GS buyers.

But there’s no explaining away the disappointing brake feel and response. At the top of pedal travel, nothing happens, and then the brakes engage with a distinct lack of progressiveness. The result is a system that produces grabby feel and is difficult to modulate. Bottom line: The 2006 Lexus GS 300 AWD rides too harshly for traditional luxury loyalists, can’t entertain a true enthusiast, and will irritate most everyone with its poor brake pedal feel.

2nd Place – Acura RL
Normally, Michelin Pilot tires are among our favorites, but the 2005 Acura RL’s 245/50R17 HX MXM4 meats spend lots of time on their sidewalls when pushing hard on a twisty two-lane. The RL tosses its 3,984-pound curb weight around at every bump and kink in the road, unsettling the car and negating some of the SH-AWD’s handling benefit. Considering that the RL’s specs are essentially the same as the Lexus and Infiniti – double wishbone front and multi-link rear suspension with stabilizer bars; four-wheel vented disc brakes with ABS with EBD and brake assist; electronically-controlled vehicle speed-sensing rack-and-pinion steering – it’s amazing how chubby the Acura feels on writhing blacktop.

Near the limits, however, the Acura is better behaved and more predictable than the somewhat schizophrenic Lexus. Part of the credit must be handed to the SH-AWD system, which makes a noticeable difference if you’re driving the RL back-to-back with the competition. You can almost feel the outside rear wheel digging in and thrusting the car out of a tight turn. Plus, the steering did the best job of communicating texture and fine detail about the road surface, and the brakes were the easiest to modulate even if the ABS did engage sooner than we might have liked. Finally, the Acura featured the best ride quality, providing an excellent balance between soft and sporty. As one tester said: “You’re always aware of the road surface, yet rarely disturbed by it.”

Bigger wheels wearing performance rubber, combined with thicker stabilizer bars, would go a long way toward putting the Acura RL into contention for the blue ribbon in this category – especially if that supple ride quality could be retained. But out of the box, the Acura is good for second-place.

1st Place – Infiniti M35x
When it comes to fun, at least in this trio, the 2006 Infiniti M35x is the car to drive. Like the Acura and Lexus, the Infiniti rides on a double wishbone front and multi-link rear suspension, equipped with front and rear stabilizer bars. The brake discs are vented at each corner, and equipped with ABS, EBD, and brake assist. An electronically-controlled, vehicle speed-sensing rack-and-pinion steering system directs the lower-profile 245/45 all-season Goodyear Eagle RS-A tires, sized 18 inches while the Lexus and Acura roll on smaller 17s.

Though it specs out like the competition, the difference is in the details, because the M35x drives very much like a BMW on your favorite back road. As long as you’re using the recalcitrant transmission’s manual mode, all the parts and pieces harmonize in a way that erases them from consciousness. Instead of thinking about how the ABS is spoiling the fun or how the tires are pushing too wide or how the brakes are hard to finesse – the M35’s hardware lets the driver concentrate on the road. Like the best BMWs, this Infiniti works in the background, instilling confidence and responding instantly to commands. It is quite pleasurable to drive hard and fast. At least until the VDC crashes the party like a drunken frat boy through a plate glass window – but that can be shut off.

True, typical luxury car buyers usually don’t drive hard and fast. When it comes to the Infiniti M35x, such customers might complain about a stiff ride quality, or abrupt brake pedal response, and that might be enough to send them over to the Acura dealer to check out a cushy new RL. That’s fine. We’re sticking with the yummy Infiniti M35x.