Used 2012 INFINITI M Pricing

Performance

The Infiniti M Hybrid owes its fleet-footedness to a 24-valve, DOHC 3.5-liter V6, an electric motor and a lithium-ion battery (which offers more than twice the power density of the nickel-metal hydride batteries found in many hybrids). Combined, they provide 360 horsepower, while a seven-speed automatic transmission channels power to the rear wheels.

Infiniti has used new technology developed in-house to power the M Hybrid, turning to a setup that it calls the Infiniti Direct Response Hybrid system; this parallel hybrid system uses two clutches, one electric motor and no torque converter. Relative to the technology used by manufacturers like Porsche and Lexus, this system allows the M Hybrid to travel solely on electric power at higher speeds — up to 62 mph, for up to 1.2 miles at a time — thus facilitating greater fuel efficiency. The M Hybrid handles adroitly as we snake down winding blacktop, another benefit of Infiniti's hybrid system because its chassis response is more direct and linear than you'll find in most other hybrids.

Whether we're on the highway or on surface streets, we're left feeling that there's never a power deficit in the M Hybrid and this impression is confirmed at the test track. In Edmunds testing, the hybrid gets to 60 mph from a standstill in just 5.2 seconds, a time that ties that of the V8-equipped M56 and beats the 5.8-second sprint time of its rival, the GS 450h.

Various modes allow us to tailor our driving experience. The car's reflexes are painfully dull in "Eco" mode; this is a setting for only the most die-hard hypermilers. Response is sharp in "Normal" and even better in "Sport." Settings are changed with a knob, a setup that allows the system to remember your selections even if you've been in and out of the car; unlike some other luxury models, the setting doesn't default to "Normal" every time you start the engine.

The whole point of Infiniti's hybrid whizbangery is to create a powertrain that hauls down the road like a V8 while sipping gas like a modest 4-cylinder. Mission accomplished, because this car nets an EPA rating of 27 mpg city/32 mpg highway and 29 mpg combined, making it more fuel-efficient than the Lexus GS 250h (22 mpg city/25 mpg highway) and placing its mileage within spitting distance of that offered by four-cylinders like the Hyundai Sonata (24 mpg city/35 mpg highway).

But there are a couple of caveats here. First, though the car's fuel mileage is great for the hybrid-sport-sedan segment, there are other, less performance-oriented hybrids that will save you more at the pump — choices like the Lincoln MKZ Hybrid, which gets 41 mpg city/36 mpg highway. Second, keep in mind that while "Sport" mode offers the most fun, you'll pay a cost when it comes to mileage. Our test car was almost always in this setting and achieved fuel economy of just 21 mpg combined.

Comfort

Ride quality is reasonably gracious throughout, even in the stiffer "Sport" setting. Still, those seeking the softest luxury car ride may come away disappointed.

The long seat cushions allow for ample thigh support and seatbacks feature bolstering that offers meaty support in sharp turns. The bolstering didn't impede comfort but we imagine that they could be somewhat constricting for those with wider frames.

A true luxury car offers a certain level of tranquility once its doors are closed, and the M Hybrid delivers on this front. Whether we're threading through traffic on the highway or charging down secluded mountain roads, the cabin remains impressively quiet.

Function

As we pull out of a parking space, pedestrians are given warning of our approach thanks to Infiniti's Approaching Vehicle Sound for Pedestrians (VSP) system. The system offers a range of sounds and functions automatically from start-up to about 15 mph. Infiniti is the first hybrid manufacturer to offer this as a standard feature.

We try to stow a tall water bottle and find ourselves out of luck, since the M Hybrid's door bins have no cupholders roomy enough to serve this function. We're more impressed with the storage bins in the car's bi-level center console, which are quite spacious and score points for featuring felt lining on both tiers. Felt also makes an appearance in the generously sized glovebox, which is lined in the fabric from top to bottom.

A touch like this connotes luxury, as do some of the car's thoughtful features. There's a light in the door handle that automatically illuminates at night to allow easy entrance. There's also a climate-control feature that Infiniti calls Forest Air, which varies air flow throughout the cabin in a way that mimics that of a gentle breeze.

In the second row, there is enough legroom for a passenger of roughly 6 feet, with the front seat adjusted for a passenger of the same height. Like the front seats, the backseats are bolstered for a sporty fit. Rear headroom is adequate but the car's sloping roof line means that taller passengers may graze their coifs on the headliner. The backseat is comfortable for two, but three passengers would make for an unpleasantly tight squeeze.

Trunk space looks good relative to that of the GS 250h — 11.3 cubic feet for the Infiniti versus 10.3 cubic feet for the Lexus. Though the space is shallow, the trunk is roomy enough to simultaneously tote golf bags and a standard-sized suitcase. Visibility is good, with a porthole behind the C-pillar helping to provide a relatively expansive view.

Design/Fit and Finish

The Infiniti M35h may be a luxury sport sedan, but as far as its sheet metal is concerned, it's all sport. The bulging lines of its exterior make the car look like it's been juiced with steroids and hint at its exciting performance capabilities.

Luxury rules within the cabin, though, with superb materials quality and soft-touch surfaces achieved via exquisitely quilted leathers and richly textured plastics. Still, some buttons feel a bit plasticky, though all the knobs that we twist feel substantial and nicely weighted.

Who should consider this vehicle

The 2012 Infiniti M Hybrid is the best game in town for the driver seeking a sport sedan offering exactly what Infiniti touts in the car's marketing literature: V8 performance with four-cylinder fuel efficiency. Its handling and performance are right up there with that of gasoline-model sport sedans, which makes it worth a look — even for those who would normally never consider driving off the lot in a hybrid.

Others to Consider
BMW 3 Series Diesel, Lexus GS 450h, Mercedes-Benz E-Class Diesel

The manufacturer provided Edmunds this vehicle for the purposes of evaluation.