babypuppi: [12] 2006 Bmw 550i Horsepower Making Today Picture

We compared three of the latest V-8 midsize luxury sedans for this test. We haven't yet tried the Mercedes-Benz E550, though a little word on pricing: the six-cylinder E350, which we have driven, costs as much as the V-8 Jag. Unlike their full-size siblings (save for the M56, which is the top-end Infiniti), price becomes a serious issue when simple options get piled on. Let's take a quick look at the volume leader, the BMW 550i, and head over to its improved competition.

2011 BMW 550i

(BMW)

"I want to sleep in here," said my girlfriend Eliana, nestled in the BMW's cream leather seats.

Indeed, our 550i had the most comfortable chairs I've ever sat in, save for the same "multi-contour" seats in the bigger 7-Series. The two-tone, wood-swathed dashboard and silky twin-turbo V-8 that debuted in the 7 are also here, as is the "Dynamic Handling Package," a $4,900 choke collar that tenses and relaxes the car's muscles to great effect.

For $78,825 — a sky-high price for a midsize luxury sedan — BMW should include a real mattress. Yet not even the larger Audi A8 or the feather-sprung Mercedes S-Class coddle occupants like this BMW. And our car had a lot of silly trinkets, like soft-closing doors and a distracting night vision camera.

If there's major failure, it's the exterior styling, to which BMW has sunk to near-vanilla lows. Save for the sweeping taillights and LED headlamp rings, the 550i — with its flat-nosed, shapeless front — is another generic sedan. The oddest feature has to be the regenerative braking system, something hybrid cars use to recharge their battery packs while coasting and stopping. At an observed 14 mpg, this 550i is no hybrid, and all the system does is make the car feel like it's dragging dead weight.

Maybe the older, lighter 5 Series cars are the ones to have, like the E39 540i sport with the six-speed manual. I've never tried them, so I can't compare. But I've never been so refreshed while sitting in traffic. And when the road opened up, I became the typical BMW show-off. Good to know the 5-Series will never bore its driver to sleep.

2011 Infiniti M56x

(Nissan)

The previous Infiniti M marked the last of the company's disjointed models that had tried and failed to imitate BMW. Granted, the 2010 M was a great sport/luxury value, with rear-wheel-drive, potent V-8, and capable chassis. But the company's nascent design DNA — birthed by the sleek G sedan and radical FX crossover in 2003 — still hadn't mated with their midsize M. At that time, Infiniti was selling rebadged Pathfinders and Maximas, along with forgettable Japanese-market Nissans like the first M45 and Q45.

Maybe that's because Infiniti didn't break into Europe, the bastion of sophisticated car design, until 2008. And what a coincidence: two years later, thanks to the fresh stamping on this 2011 M56x, the company's design language speaks as one.

It's far more expressive than BMW. In the middle of all those voluptuous curves and hood bulges is a bowed, straight-lined chrome grill. Inside, arching sweeps of dark wood and wavy stitching on the seats surround the tall, curving center stack. On our model, padded leather covered the dash and even the foot wells, where knees tend to knock against hard rubber or plastic in most luxury cars.

While Infiniti crams the center stack with buttons, on the M56x they're easy to work since the stack is divided into two tiers. High-tech gear is indeed everywhere. A button on the steering wheel can be customized to activate one or several safety features, like the lane departure system that literally nudges you back should you drift over the line. Or the "Intelligent Brake Assist," which uses a laser to detect slow-moving cars and can slam the brakes, similar to the "City Safety" system pioneered by Volvo.

Switching on the adaptive cruise control puts the M56x in full auto-pilot. We tried it during rush hour in the Ted Williams tunnel — foot above the brake pedal, just in case — and sat back as the M56x slowed down, stopped, and restarted without any driver input. It's so good Infiniti owners should be allowed to text while driving.

Our fully-loaded V-8 model, with all those gadgets and all-wheel-drive, topped out at $68,425 with destination, still $10,000 below the BMW. Unlike the 5-Series, the sport package can't be paired with all-wheel-drive. There's no manual transmission either, and we were disappointed the G37's superb magnesium paddle shifters were missing on the 7-speed automatic.

For this comparison, we'd have liked the rear-wheel-drive car equipped with the sport package and those sinister 20-inch wheels, since our tester's flaccid suspension killed any sporting intentions. To blunt criticism of the old M's harsh ride, Infiniti went soft and dialed in too much rebound. It's no help on the highway, where the M's body floats over dips and bumps, the steering numb to the road surface. The 5.6-liter, 420-horsepower V-8, however, is an onramp terror.

If you want the latest and best technology in a striking wrapper, the M is a good choice, but for $70,000, there are better-balanced sedans out there.

2011 Jaguar XF

(Dan Roth; all others courtesy Jaguar)

Can a Jaguar be considered a value? The shapely XF sedan has standards at every curve: V-8s across the entire lineup (three, in fact), navigation with Bluetooth and iPod support, power heated seats, rear parking sensors, and keyless ignition. Price a similar Mercedes-Benz E-Class or BMW 5-Series and you'll head north at least $10,000.

The XF stirs us with its satisfying blend of style, speed, and comfort — the must-haves of the midsize luxury segment — all for a starting price of $53,375. That's what most of the competition charges for their six-cylinder models, with almost nothing included. Sure, you could spend $80,000 on the fully-loaded XFR. At that price, you'll humiliate the BMW with 510 horsepower and a thoroughly evil body kit. A lesser 470-horsepower XF Supercharged slaps our Infiniti for $67,000.

The price gap leaves some minor drawbacks. The touch-screen display is low-resolution, clunky, and slow. Because of the coupe-like roofline, the backseat is a bit short on leg- and headroom. Some of the advanced features on the other two are missing, like how the Jag's adaptive cruise control doesn't halt the car to a stop in traffic. Lane departure and all-wheel-drive aren't available, either. To compensate, there's a "winter mode," but without snow tires you'll need a shovel even for the lightest powder.

Yet that's it. The sexy body has inspired all sorts of clones, like the Volkswagen CC and 2011 Hyundai Sonata. It's elegant and full of details inside, like a leather-stitched dash, a touch-sensitive glove box opener, and power-closing air vents (though the latter two smell like pricey electrical repairs). Unlike the compact, Ford-based X-Type of the early 2000s, the XF is not a watered-down Jaguar.

Performance is as easy as taking a breath and letting the 5.0-liter V-8 exhale its deep torque and throaty exhaust note down the highway. Down two gears from the BMW, the 6-speed automatic is a smooth box, quick to respond to the slightest jab.

The steering and suspension have an innate connection with the tarmac, while grip and ride comfort are sublime in every situation. Where BMW relies on driver-adjustable dampers and steering to do that, Jaguar tunes their springs the old-fashioned way. As such, the XF feels more natural and agile than the 550i, and doesn't exhibit the handling compromises that plague the M56.

Tech freaks won't appreciate this Jag. But while the XF could upgrade its electronics, the 550i and M56 need to get the basics down. This is our choice, if not on the price alone.