2012 Infiniti M56 Review

2012 Infiniti M56 - Infiniti's midsize luxury sedan M56 is modern-day American muscle car for the country club crowd.


Vehicle Tested
2012 Infiniti M56x
Base Price: $61,600
As-Tested Price: $66,925
Built in Japan.

Deluxe Touring Package
18-inch Wheel Package

Engine: 5.6-Liter V8
Transmission: 7-Speed Automatic

Drive Wheels: All-Wheel Drive
Midsize luxury sedan is a catchall phrase that's similar to saying "right-handed pitcher" in baseball. Some righties are tall-thin fire balling monsters and others a short, slightly pudgy puff balling specialists. Most fall somewhere in between. Such is the case for midsize luxury sedans.

Most seat four adults in a modicum of comfort, offer V6 or V8 power and are rolling technology test beds that have enough electronics and safety features to make the international space station blush. The problem when categorizing them is that midsize luxury sedans range widely in price and mission.

Competitors in the segment include, but are not limited to, the Acura RL, Audi A6, BMW 5-Series, Buick LaCrosse, Cadillac CTS, Jaguar XK, Lexus GS, Lincoln MKZ, Mercedes-Benz E-Class, Volkswagen CC and Volvo S80. The Infiniti M lives toward the top of the bunch, being one of the larger cars inside and out and also carrying a hefty price tag that can approach $70,000.

The current-design Infiniti M dates back to 2006 and shares some components and engines with the smaller Infiniti G. It comes only as a five-passenger four-door sedan.

Three distinct models are offered. M37 comes with a 330-horsepower 3.7-liter V6 engine. M56 comes with a 420-horsepower 5.6-liter V8. Both are available with either rear- or all-wheel drive. Sandwiched between the M37 and M56 is the new-for-2012 M Hybrid, which combines a 3.5-liter V6, electric motor and battery pack to generate 360 horsepower. The hybrid is only offered with rear-wheel drive. Sole transmission offering for all models is a seven-speed automatic.

Standard safety equipment on all models includes antilock four-wheel disc brakes with brake assist, stability control, traction control, front-seat active head restraints, tire-pressure monitor, wiper-activated headlights, emergency inside trunklid release, rear-view monitor, and dual-front, front-side and curtain-side airbags. A Technology Package that's available on all models includes dlind-spot alert and intervention, lane-departure warning and intervention, Intelligent Brake Assist with collision warning and pre-crash tightening seat belts.

The rear-drive M37 lists for $47,700 while the all-wheel-drive M37x starts at $49,850. Standard equipment includes air conditioning with dual-zone automatic climate controls, interior air filter, power tilt-telescope leather-wrapped steering wheel with radio controls, cruise control, leather upholstery, heated ten-way power front bucket seats with lumbar adjustment, memory system (driver seat, mirrors, steering wheel), trunk pass-through, wood interior trim, heated power mirrors with tilt-down back-up aid, power windows, power door locks, keyless entry, keyless access and starting, sunroof, AM/FM/CD/MP3 player with USB port and satellite radio, Bluetooth cell-phone connection, active noise reduction, trip computer, rain-sensing variable-intermittent wipers, illuminated visor mirrors, automatic day/night rearview mirror, outside-temperature indicator, universal garage door opener, rear defogger, automatic headlights, floormats, theft-deterrent system, HID headlights, fog lights, 245/50VR18 tires and alloy wheels.

The V8-powered M56 comes in at $59,200 with rear drive and $61,700 in all-wheel-drive M56x trim. Additional standard features includes navigation system with voice recognition and traffic information, heated steering wheel, cooled front seats, Bose sound system and music hard drive

The M35 Hybrid comes in at $59,200 and includes the equipment found on the M37. Options include adaptive cruise control, sport package, rear spoiler and unique alloy wheels. Destination charge is $895 and the M is built in Japan.

Get Up and Go  Though the M is a large and heavy vehicle, the V6 engine provides good acceleration from a stop and decent passing power. It's no hot rod, but that's reserved for the tarmac snorting M56, which races from 0-60 mph in an adrenaline pumping five seconds. Blindingly quick, even for this class.

Transmission smoothness is on par with others in the class but still could be better. Downshifts are measured instead of crisp and prompted only with a deep stab on the throttle.

Fuel economy ranges depending on model. The M37 rates a respectable 18/26 mpg in the EPA cycle. M56 models offer more meager results of 16/24 mpg. Hybrid models are rated at an impressive 27/32 mpg overall. All models require premium-grade gasoline.

Though the EPA ratings for the M56 are so-so, that's to be expected for a large vehicle with a big V8 under the hood. Still, given a light throttle foot and a good dose of relaxed highway cruising it's easy to average about 22 mpg. Throw in some stop-and-go city driving and the average is likely to drop into the high teens.

On the Road  Regardless of model, the M has impeccable road manners. The M37 offers the most balanced ride with good impact absorption and rebound control. Stepping up to the M56 or opting for the sport package on the M37 seems to unsettle the car overall as the firmer suspension and larger wheels and tires can impact ride comfort on badly broken roads. Thankfully the body never pitches or bounds, regardless of model or road quality.

Make no mistake the M is a large car and acts more like an agile power forward than a lithe point guard. Still, the steering is nicely weighted and dead accurate, the brakes are strong and easy to modulate and body lean is kept to a minimum. That, combined with the fine weight balance and grippy tires, is a recipe for a car that's fun to drive fast through the twisties.

Engine, wind and road noise are well muffled, no doubt thanks to plenty of sound insulation and the active noise cancellation system. Engines produce a hearty growl in hard acceleration that's appropriate for the price. Sport package tires grow noisy on concrete surfaces.

Behind the Wheel  When the M was introduced back in 2006 the interior was a revelation in the class. Materials were top notch and the control interface was second to none. Fast forward half a decade and the competition has, for the most part, caught up to the M. Yes, materials are still quite good and assembly quality is impressive, but the gauges feel a little dated when compared to some of the electro-luminescent dials offered on competitors. The navigation screen seems a little small, but is still quite easy to see and program. Overall, it's a testament to how good that 2006 model was more than a statement on how Infiniti has improved it since.

Front seats are nicely padded and quite comfortable--if a bit firm. Head room and leg room are exceptional and outward visibility is excellent. Getting in and out is a snap as the door openings are wide and the hip point of the seat seems to be higher than in some competitors.

Rear seat occupants are treated well. Leg room is good, but head room marginal for those more than six-feet tall and foot space grows tight if the front seats are all the way back--thanks to a tall drivetrain tunnel that also limits seating three across. Rear doors are large and open wide.

Cargo space is adequate for the class but the trunk shape is irregular and not very deep. Also, the rear seats don't fold. Instead, there's a narrow pass through that's not really useful for hauling much beyond fluorescent light tubes. Interior storage is meager with just a few covered and open bins. Thankfully the center console box has two tiers, one for smaller items and one for large items.

Bottom Line  Midsize premium luxury sedans aren't cheap and the Infiniti M is no exception. Still, you're getting a lot for your money and, in the case of the M, a fun-to-drive car as well. Opt for the V6 unless you must have the power of the V8--especially as gas prices climb past the $4.00 mark nationwide.

Specifications, 2012 Infiniti M56x
4-door sedan
Wheelbase, in.
Size, liters/cu. in.
5.6 / 342
Length, in.
Horsepower @ rpm
420 @ 6000
Width, in.
Torque (lb.-ft.) @ rpm
417 @ 4400
Height, in.
7-Speed Automatic
Weight, lbs.
EPA Estimates, mpg
16 city / 23 highway
Cargo Capacity, cu. ft.

Fuel Capacity, gals.
Manufacturer's Warranty
Seating Capacity
4 years / 60,000 miles
Front Head Room, in.
6 years / 70,000 miles
Front Leg Room, in.
7 years / Unlimited miles
Second-Row Head Room, in.
Free Roadside Assistance
4 years / Unlimited miles
Second-Row Leg Room, in.
Free Scheduled Maintenance

Mark Bilek

Mark Bilek is the Senior Director of Communications and Technology for the Chicago Auto Trade Association and the General Manager for DriveChicago.com. He is also responsible for developing and maintaining the Chicago Auto Show Web site.

Mark has been reviewing vehicles for more than two decades. Previously, he was associate publisher at Consumer Guide, where he oversaw publication of Consumer Guide Car & Truck Test, Consumer Guide's Used Car Book, and ConsumerGuide.com. He was also responsible for publication of "Collectible Automobile" and various hardcover automotive titles. In 2001 and 2002 he served as president of a Midwest Automotive Media Association. Mark has appeared on NBC TV, ABC TV, Fox News, WGN and MotorTrend TV as an automotive consultant. He hosts the Drive Chicago radio show on WLS 890 AM and was a regular guest on WGN Radio's Steve & Johnnie show. Mark lives in the northwest suburbs with his wife and three sons.