The 2013 Infiniti M is offered in three flavors: M37, M56, and M35h. Among them, the M37 is the most affordable and top-selling from the lineup; it's powered by a 330-horsepower, 3.7-liter V-6. Meanwhile, the M56 has a 420-hp, 5.6-liter V-8, and the M35h packs a V-6 and special hybrid powertrain to produce up to 350 combined horsepower.
The M37 has strong acceleration and is quite quick, but this engine, especially in the M, is too raucous and coarse-sounding for the personality of the car. On the other hand, the V-8 M56 has a brash, baritone engine note that's more fitting, accompanies by neck-snapping responsiveness. Both engines pair up with a seven-speed automatic transmission with a manual-shift mode, rev-matching, and available paddle shifters.
No matter which of these versions you go with, you'll get a seven-speed transmission that's happy to pound out quick, unobtrusive gear changes at your command when the automatic’s moved to manual mode; it also rev-matches downshifts very effectively. And with four individual settings (Sport, Normal, Eco and Snow), you can change the way (and when) the transmission shifts and how the accelerator pedal respond to inputs. You’ll be fine leaving it in Normal almost all of the time.
The Infiniti M35h has a rather different powertrain setup; it gets a Direct Response Hybrid system that's performance-oriented and delivers more than 350 combined horsepower yet is rated at an EPA 27 mpg city, 32 highway. Unlike some other hybrids, it has a transmission with actual gears--seven speeds--and is easier to drive through curvy stretches than nearly any other hybrid. Its suspension is tuned a bit more softly than the other models though.
Otherwise, Infiniti nailed the calibration of the suspension in the M37 and M56. Both have great handling, quick, responsive steering, and ride quality that's not quite supple but definitely not harsh or too noisy. supple ride--are an elusive mix, and Infiniti's nailed it. The steering has the right weight and turn-in feel. The rear-wheel-drive chassis is balanced and responsive for such a long car.
On either of the non-hybrid models you can add all-wheel drive (M37x, M56x), and it doesn’t dull the edge too much. A feature called Active Tracing Control helps manipulate power levels and anti-lock brakes to help cornering feel a little more surefooted and balanced, and big, strong brakes on all versions come standard with lots of pedal feel.
To maximize that performance, there's a Sport package adding 20-inch wheels, four-wheel active steering, sport seats and steering wheel, and aluminum pedal trim to rear-drive versions. It's our preferred setup, as it's not too hard, yet not overly soft like a luxury car. Overall, this is a car that drives like a car that's one step smaller.