2014 Acura RLX

The differences that can't be seen are intangibles like heritage, prestige, and word of mouth.

To hit on the point we're building to: The challenge for any luxury sedan today is to hit some benchmarks that would have been coachbuilt in a bygone era. The Audi A7 and Jaguar XF are in the RLX's periphery, and they faintly reek of sophistication and substance--nevermind the Cadillac XTS and its flair-filled, jewel-blinged bod.

The RLX? It's less apt to leap off a runway. The stance is right, and the proportions are good, and even the BMW-esque turn to the roofline has enough distance between it and the original to claim its own birthright. The rest is subtle but graceful, from the LED headlights to the curve stamped over the front wheels to the LED taillights. As rolling stock, the RLX's smoothly arched roofline and somewhat aggressive stance are attractive--but they're not groundbreaking.

The cabin is a pretty functional, handsome place to check off driving tasks, but it's more of the same. It falls in the gap between the opposing ways drivers tend to define luxury: it doesn't wrap itself in the precisely modern design cues that define most Audi cockpits, or in the pervasive sense of old (and new) money that fills every Jaguar cabin. Cadillac is doing fantastic interiors in this class, too, and the choice of materials and grains and glosses are as point-perfect in the Acura RLX. It has the sense of refinement down pat, but lacks the sense of drama that's almost a basic requirement in an age of A7, XF, and XTS.

It's an aural component that puts some waveform into the engine's straightforward delivery. There's not much urgency in the way it pulls uniformly away from a stop, or in its relaxed uptake. It's a contrast to the Lexus GS, which has some peaks whipped into its performance, though it doesn't necessarily feel any quicker than the Acura RLX--both sit squarely in the 6-second 0-60 mph range.

The RLX's automatic transmission nets shift paddles and a sport shift mode this year, but no more gears. It's a six-speed automatic with very smooth upshifts, less invisible downshifts. The top-rated sedans in the segment are changing over to eight-speed automatics, as is the Chrysler 300. The ZF eight-speed that's nearly universal sets a high bar, and the RLX could use more tightly spaced gears to accelerate more quickly off the line.

As for the gas mileage benefits of more gears, the RLX doesn't need much help. It's estimated at 20/31 mpg, or 24 mpg combined, near the Chrysler's numbers with two fewer gears.

Step up a notch, and you get to the RLX Sport Hybrid SH-AWD model, which packs a special new three-motor hybrid system that previews technology to be used in the future NSX supercar. With a 3.5-liter V-6 and a new seven-speed dual-clutch automated manual gearbox that has a 35-kW motor built in, what's under the hood already has the makings of a strong, smooth hybrid system. But what makes it a fun, all-weather machine is that there's also a new Twin Motor Unit mounted to the rear subframe, including two 27-kW motors that can act together, on their own, or in a regenerative mode to add available traction or to affect the car's composure in corners.

In all, the SH-AWD hybrid system makes 377 horsepower and 377 pound-feet of torque.

How does the RLX handle? It really depends which model you go with. Along with the XTS, MKS, and Volvo S80, the front-drive model is in a niche divided from the traditional luxury marques by heritage as much as orientation. At BMW, Mercedes, and Jaguar, rear-wheel drive is the norm, and all-wheel drive is an option for marketing's sake. Audi is the grey area.

Acura's on the other side of the fence. The RLX and the RL before it have always been front-drivers, and the dynamic difference between Acura and those brands has only shrunk a little bit. The RLX has a conventional suspension tuned for comfort first, with a bit of lively feel dialed in via electric power steering and a trick pair of actuators at the rear wheels. The RLX's steering has a light touch on center that's very noticeable at parking speeds, entirely intentional, before it transitions to a more consistent heft. The transition's less obvious at speed, where the ability to steer its rear tires becomes the RLX's most significant new hardware bullet point.

The RLX's rear steering--Precision All-Wheel Steer, or P-AWS--is technologically extravagant, for what the RLX wants to be. P-AWS puts an actuator on each rear wheel and keeps tabs on vehicle speeds and steering motions, so it can feed in minute amounts of rear-steer to give the RLX more stable road feel. In lane changes, all four wheels move in the same direction. On a curving road, P-AWS can steer the rear wheels up to two degrees in the opposite direction of the front wheels, to cut a sharper line. It's an effect that can be helpful in daily driving, mitigating some of the width that's been baked into the RLX's platform (maybe for interior room, maybe also to accommodate some of the hardware on the way in the RLX hybrid and NSX).

Under extreme conditions, like on the stretch of Sonoma Raceway where Acura let us press the system, P-AWS can make you rethink the way you approach corners and react to them, by virtue of the way it transitions through its rear-steer spectrum. Drive it quickly in an uphill straight line, then dive down and deeply left, and the quick oversteer set up by P-AWS is unlike any other system before it. It's a glint of edge in a car that doesn't necessarily need for one, or pretend to one.

The powertrain and steering work in concert with a conventional suspension design to give the RLX a comfortable, composed ride. It's sprung and damped well enough to absorb stretches of broken pavement with little fuss, and it leans into corners casually and undramatically. For that kind of driving duty, you'll never miss an adjustable suspension system or adaptive shocks like the ones commonly found on competitors, but absent here. Those systems can be tailored to a wider range of performance limits, and the RLX doesn't intend to ultra-high performance. There's no M or AMG edition in the works. It's a mono-spec machine that knows its limits, and makes the best of them.

Go with the Sport Hybrid SH-AWD model and you should ignore the last several paragraphs entirely. This is the model to have, if you like the idea of an under-the-radar sport sedan with surprisingly good dynamics. Head into a corner a little too hot, and using what feels like physics-defying magic at the rear wheels, the RLX sends power selectively to each of the rear wheels—the outside rear wheel especially—nudging your trajectory back right where it should be. It's rather unsettling at first, because you feel that nudge from the driver's seat, but not through the steering wheel.

But the novelty doesn't wear off. We can see the RLX's attributes being just as useful on a weather-slicked highway, making an emergency maneuver, as we can on the mostly empty backroads where we test-drove the RLX.

Otherwise with the Sport Hybrid, it's extremely responsive to stabs of the accelerator, and it accelerates almost like an electric car--with the motor systems filling in neatly wherever you can hear the dual-clutch gearbox grab for the next gear. It's an entirely different, more exotic (and exciting) driving experience than in the front-drive RLX--and a bit out of sorts, given the conservative presentation.

It makes an impact more when you open the door--that's when the RLX keys up, emits a little jingle (yes, a jingle) and shimmers its displays in a slightly fancy display of emotion we've never seen from Acura. The interior looks large, and it's not all visual tricks, though the clever stylists have boxed out the door panels and boxed in the central tunnel to create rectangular passenger spaces that read more like architecture than car design.

In front, the seats fit like broad-backed executive desk chairs. They adjust 12 ways and have heating, and optionally, ventilation. Acura says shoulder room is among the best in the category, though their chosen competition is more German than American, something we differ with. The center console is wide, but so are the passenger spaces, and headroom is fine for tall adults, even without having to lean back in those well-done chairs.

The back seat? It looks enormous, and the rear door cuts are usefully large, making it easy to slide into the three-passenger space. The cushions are wide and long under the leg for great support--but even with a slouch, I still rubbed my head on the ceiling, something that happens regularly in Passats, Accords, and Fusions, but never in the MKS or XTS. There's somewhat less shoulder room than expected, too. The rear seats can be optioned up to heating; our ancestors would probably be disgusted at how far from the hunter-gatherer tribe we've fallen, but who doesn't like a warm cheek or two?

Acura's fitted the RLX with plenty of small-item storage. The center console's the foremost space to hide valuable objects, since its lid opens from either side, or slides with a lovely damping toward the rear. The trunk has a slight 15.3 cubic feet of space, or less if you get the top audio systems; it's a flat floor, but it's a couple of gym bags smaller than the trunk on the MKS.

We were impressed duly by the uptick in materials used in the RLX. Our late-run prototypes didn't show much evidence of being test cars, and the presence of engine note is a welcome change for Acura--not noise to be filtered out, we think. The tire noise? That's something the RLX's hollow-core wheels were meant to address, but don't always nix completely.

All RLX sedans come with the usual airbags and stability control. A driver-side knee airbag is standard as well, and so are a rearview camera and Bluetooth, two features we consider almost essential in everyday driving due to driver inattention. The RLX's rearview camera actually displays a 180-degree view of its surroundings, for even better visibility. It helps too that the RLX doesn't have the very thick roof pillars or very small rear glass of, say, the Lincoln MKS.

Among the options offered to RLX buyers are blind-spot monitors, a feature we like for the added information it gives drivers who fail to check their rearview mirrors. There's also adaptive cruise control and a lane-departure and lane-keeping system; together with a collision-avoidance system, the chorus of sensors and alerts can actually prevent lower-speed accidents--and even can grant a degree of autonomous driving. When the adaptive cruise control is set, the RLX will stop itself at lower speeds--and all the driver has to do to re-engage is to hit "resume" on the steering wheel, or tap the gas. The RLX will even steer along with the vehicle ahead at very low speeds. It's clever, it's creepy, it's a step too far toward divorcing the car and the driver--you pick. To us, it's mostly an expensive, unnecessary frill.

And finally, for safety's sake, the RLX loses one of the features we've long appreciated in Honda and Acura vehicles. Acura now blocks out any user from entering touchscreen information when the vehicle is moving. The logic's unassailable if the driver's the only passenger--but what about other passengers? In this case the "feature" becomes an annoyance.

The $51,845 RLX with Navigation adds the GPS with voice commands; AcuraLink, a suite of services discussed below; and a color LCD display between the primary gauges. The $55,345 RLX with Technology Package upgrades the wheels to 19-inchers and refines the leather choice to "Milano" hides; adds blind-spot monitors, acoustic glass, and four more speakers; and caps it with retractable side mirrors and rain-sensing wipers.

The 2014 RLX carries Acura's standard warranty of four years or 50,000 miles.

Of all the new features integrated into the new RLX, the AcuraLink system and the dual-screen output of the infotainment system will take the most time to learn and to use. The logic behind both sounds reasonable. AcuraLink's basic setup uses a smartphone app, Aha, to be the gatekeeper for dozens of other apps like Facebook. With one link they're all accessible through the head unit, and new information like points of interest can be accessed without massive, regular updates. Still, it's an additional interface between the driver and safe driving--something the best and simplest systems like a simple smartphone mirroring setup will do best. AcuraLink also offers paid services to connect to live operators, a service we've never been sold on in the smartphone era, in any case.

The dual-screen setup? It's an interesting spin on the complexity of systems like MyLincoln Touch and Cadillac CUE. By splitting functions, Acura hopes to keep the non-touch-displays on the larger, more visible screen, while controls like audio toggles are placed closer to the driver on the smaller touch-sensitive screen. On some models, the third screen in between the gauges offers still more information.

The result, though, is a duplicative, sometimes confusing interface that feels like a compromise around an existing dash architecture. It gives us pause about the coming dual-screen setup in the Infiniti Q50--never mind the agita we already get when we climb into single-screen systems like those in the Cadillac XTS or the Lincoln MKS.

Apple, Google, Samsung--someone, please save us?

Models with an all-new Sport Hybrid system will be the best-performing in the lineup, not only from a performance perspective but from a green one. EPA ratings for these jump to 28 mpg city, 32 highway, from the new triple-electric-motor hybrid system and lithium-ion battery pack, in addition to the 3.5-liter V-6.