Review: 2011 Infiniti M56

Up Front

There's no doubt that the new V8-powered Infiniti M56 sedan is a very hot car, as well as a big improvement over the model it's replacing, the slow-selling Infiniti M45. But will the M56—with its smaller, less expensive sibling, the M37—be a blowout success for Nissan's (NSANY) luxury division the way its hot-selling G37 has been? I have my doubts.

If you're into luxury with a healthy dose of horsepower under the hood, Infiniti's new "M" sedans offer excellent value next to a comparable BMW (BMW:GR), Mercedes (DAI:GR), Audi (NSU:GR), or Lexus (TM). If you're into spirited driving and want a sport-tuned suspension, steering-wheel-mounted paddle shifters, and other such add-ons, the way Nissan has structured its option packages detracts from both models' appeal. In short, the new M sedans aren't quite the BMW-killers that Infiniti hoped they would be.

Inside, the M56 is slightly larger and fancier than the previous model. Still, the most obvious difference is under the hood: The M56 has a hugely powerful engine, a 5.6-liter, 420-horsepower V8 that generates 417 lb. ft. of torque. That's 95 more horses than the M45 has, making it the biggest engine in the segment. The only direct competitor that comes close to offering such power is BMW's redesigned 550i, whose V8 lags the Infiniti by 20 horses but generates even more torque, 450 lb. ft. The two models are neck-and-neck when it comes to acceleration: Car and Driver magazine clocked the M56 at 4.7 seconds in accelerating from 0 to 60, compared with 4.8 seconds for the BMW 550i.

Not surprisingly, the M56's starting price is roughly five grand higher than the M45's. The new model starts at $58,775 with rear-wheel drive and $61,275 with all-wheel drive. Its average selling price is $63,269, according to the Power Information Network (PIN). Budget-conscious shoppers can save thousands of dollars by opting for the M37, which has a V6 engine and less standard equipment than the M56 and starts at $47,375 with rear-wheel-drive and $49,525 with AWD. The M37 is about as quick as the M45 and gets better gas mileage.

The outgoing M45 only got 16 miles-per-gallon in the city and 21 on the highway with rear-wheel-drive. Even the M56 does better than that: With rear-wheel-drive, it's rated at 16 mpg in the city and 25 on the highway, ahead of the BMW 550i (15/22), way ahead of the Mercedes E550 (16/24), and about equal to the Lexus ES 460 (17/24). The new Infiniti M37 outdoes them all: It's rated at 18/26 with rear-wheel-drive or AWD.

One caveat about the high mileage rating of the M56: The driver has a choice of four modes (Snow, Eco, Normal, and Sport). However, throttle response diminishes noticeably in Eco and Normal. There's a big hesitation when you punch the gas, which improves fuel economy but defeats the purpose of the powerful engine. I ended up staying in Sport most of the time and got only 17.1 mpg in 229 miles of mainly highway driving.

Combined sales of the Infiniti M56 and M37 soared 61.7 percent, to 11,765, in the first 10 months of this year, compared with the same period in 2009. However, that's from a very small base. Infiniti sold four times as many G37 sedans and coupes (47,032) during the same period.

Behind the Wheel

The M56 is a fine vehicle if you stick with the base or all-wheel-drive models. In those configurations, it's a very quick luxury car with a gorgeous interior and a distinctive, curvaceous exterior that stands out from the crowd of rival sport-luxury sedans. The cabin also can be jazzed up with a $3,800 Deluxe Touring Package that adds a 16-speaker Bose surround-sound system, a power rear sun shade, a suede headliner, leather seats with a distinctive quilted pattern, and sparkling wood trim made of White Ash with silver powder rubbed into its finish.

However, the way the option packages are structured really bugs me. For starters, it would be nice to be able to get the big V8 without the vast array of standard equipment—including a sunroof, heated steering wheel and navigation system—that currently comes on the base M56. Infiniti could easily chop four grand from the starting price and make the base M56 more appealing to budget shoppers.

The bigger problem arises if you want to make either M sedan sportier. You have to take both the $3,650 Sport package (20-in. alloy wheels, bigger brakes, upgraded shocks and springs, unique front fascia, sport seats and shift knob, aluminum pedals, and four-wheel active steering, as well as very cool oversize magnesium paddle shifters) and $2,000 Sport Touring package (which includes the 16-speaker Bose surround system, as well as a "Forest" air system and power rear sun shade).

I'd like to be able to get the paddle shifters, heavy-duty brakes, bigger wheels, and sport suspension without all the other stuff. I can't stand the four-wheel active steering, which automatically adjusts the toe-in angle of the rear wheels slightly—supposedly to improve handling. My driver's notes about my test car, which had that feature, repeatedly contain the word "weird," usually referring to the car's steering, which felt heavy without offering enough of the direct connection to the road that you want in a sporty car. During hard cornering, the car seemed jumpy and a little hard to control.

Hey, Nissan: How about just offering a genuine sport suspension package and making most of that other stuff standalone options? I'd prefer not to pay extra for four-wheel steering, the rear window shade, and the "Forest" air system, which is supposed to provide a natural air-flow but made little difference that I could discern.

Also, as it now stands you can't order the sport suspension, bigger brakes, and paddle shifters with all-wheel drive. If four-wheel active steering were a standalone option, that would be a possibility. And the above-mentioned Deluxe Touring package currently can't be combined with the sport packages. It would be cool if the silver-flecked ash trim could be ordered as a separate option, along with the sport packages.

According to its stats, the M56 is as roomy as any sedan in its segment, but the front seats feel tight to me. That's partly because of the car's cockpit-style interior design, in which the center console juts out from the dash between driver and passenger. Headroom up front also is more than an inch less than in the G37. There's a hump running down the middle of the cabin floor, making the middle rear seat mainly for children. Total interior volume is actually slightly less than in the base M45.

Buy it or Bag It?

The $63,269 average price of the new M56 makes it somewhat less expensive than the 2011 Mercedes E550 ($65,122)—probably its toughest competitor if you favor luxury over sportiness. The M56 is much cheaper, on average, than its sportiest main rival, the BMW 550i, which sells for an average of $67,969, according to PIN.

There are numerous alternatives that are even less expensive, including the 2011 Audi A6, which averages $50,827, the Jaguar XF ($50,965), Lincoln MKS ($44,857), and Cadillac CTS $43,111. However, to match the power and speed of the M56 you'd have to pay up for upgraded versions of these rivals, such as the Audi S6, the Cadillac CTS-V, and the supercharged Jaguar XF, which would erase most, if not all, of their price advantages.

Personally, if I were shopping for a sporty luxury sedan in this segment, I'd go with the BMW 535i or 550i. Or I'd opt for the slightly smaller and less-speedy Infiniti G37. The G37 handles wonderfully, is a lot cheaper than the M sedans, and is available with all the usual sport upgrades—except four-wheel active steering, which Infiniti dropped as an option on the G37 this year.

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