With the addition of the M35h hybrid model this year, the M sedans are now offered in three flavors. The M37 is the more common (and more affordable) of the three, powered by a 330-horsepower, 3.7-liter V-6. Meanwhile, the M56 has a 420-hp, 5.6-liter V-8 that delivers neck-snapping responsiveness, accompanied by one of the more hellacious exhaust notes in a luxury car. Both engines pair up with a seven-speed automatic transmission with a manual-shift mode, rev-matching, and available paddle shifters.
In either version, the seven-speed transmission is happy to pound out quick, unobtrusive gear changes at your command when the automatic’s moved to manual mode; there's really effective rev-matching for downshifts, too. Like the German competition, the Infiniti M automatic also adds an optional set of electronic controls for transmission shifting and throttle response, with four individual settings (Sport, Normal, Eco and Snow). You’ll be fine leaving it in Normal almost all of the time.
As for the new 2012 Infiniti M35h, 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.
Most sport sedans sacrifice some ride quality for handling sharpness--or vice versa--but Infiniti nailed the calibration 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.
You can get all-wheel drive on either as an option, (M37x, M56x), and it doesn’t dull the edge too much. Available Active Tracing Control manipulates power levels and anti-lock brakes to help the M sedan corner more quickly. And big, strong brakes on all versions come standard with lots of pedal feel.
A Sport package adds 20-inch wheels, four-wheel active steering, sport seats and steering wheel, and aluminum pedal trim to rear-drive versions, though there's no serious performance boost. That said, it's out preferred setup, as it's not too hard, yet not overly soft like a luxury car. Available Active Tracing Control manipulates power levels and anti-lock brakes to help the M sedan corner more quickly. And big, strong brakes on all versions come standard with lots of pedal feel.