Threats come no more thinly veiled than this: By christening its new mid-size sport sedan an M45, Infiniti is warning all the world, especially BMW, that it means business. Under neatly chiseled skin, the upstart M borrows heavily from the slightly schizophrenic Q. But thoughtful recalibrations and a diet that hikes the power-to-weight ratio a healthy six percent make this a very interesting contender which every sport sedan competitor would be wise to take seriously.
Nissan's three-year-old LFR (large, front-engined, rear-drive) platform underpins both the M and the Q. A lusty 32-valve, 4.5-liter V-8 engine and five-speed automatic transmission serve both admirably. Sophisticated touches include variable intake-valve timing, variable-length intake runners, electronic throttle control (a.k.a. drive-by-wire), a hydraulically driven cooling fan, and a dual-mode muffler. While the Q's Electronic Torque-Demand system is programmed for supremely smooth delivery, the more impetuous M kicks its heels during gear changes. To boost the vitality of both upper-crust Infinitis, the final-drive ratio has been changed from 2.76:1 to a more lively 3.13:1.
Chassis blueprints are unchanged except for a 2.8-inch wheelbase snip, yielding 110.2 inches axle to axle, a mere 1.2 inches shorter than the corresponding dimension of the BMW 5-series. Suspension gear consists of a conventional strut-damper setup in front and a multi-link rear. There's a coil spring for every corner plus a security blanket of electronic controls--overseeing traction, stability, and braking functions--to keep the M45's feet perpetually on pavement. The rack-and-pinion power steering is speed-sensitive.
To gauge the pulse of its latest prodigy, Infiniti launched us toward California's sumptuous Napa Valley behind the wheel of a pre-production prototype. Our first dynamic discovery was that the M child has learned fine manners from its Q forebear. Nissan's VK45DE V-8 engine is Cadillac-quiet, Lexus-smooth, and Honda-potent. Peak outputs of 340 horsepower at 6400 rpm and 333 pound-feet of torque at 4000 rpm compare favorably against BMW's V-8s, excluding the hairy-chested one powering the M5. As if by teleportation, the M's engine sinks you deeper into the nicely shaped bucket seat with barely a murmur. Chief engineer Tatsuo Osawa proudly boasts that the speedo's glowing red needle can touch 60 mph in less than six seconds.
The steering feels tight and precise, and body roll is held in check nicely. Hopes for a V-8-powered BMW with $10,000 of change in our wallet danced until we pressed the M deep into a decreasing-radius bend. That's when resolute understeer rattled our reverie and recollections of the Q's not-quite-sorted persona brought us back to reality like an hour-early wake-up call. The combination of a slightly too slow steering ratio, not quite enough wheel travel, and ragged responses at the remote corners of the performance envelope shattered the BMW illusions. On top of that, the supposedly manual shift mode changes gears impulsively, the electronic throttle was unruly in one of the cars we drove, and the dead pedal is angled too flatly to provide secure left-leg bracing when your right leg is planting a lasting impression on the firewall.
Inside, the center of the dash dominates the scene the same way Mount Rushmore enlivens South Dakota. Plans for telematic toys went out the window with the demise of supplier Wingcast, but you can opt for radar-based cruise control and a navigation system that plays on a seven-inch LCD screen. Regrettably, the ergonomically challenged switchgear has been imported from the Q with no notable improvement. Solace comes in the form of air heated or cooled by solid-state devices, wafting pleasantly through the bucket seats' perforations.
Infiniti earns an A for mustering the courage to attack BMW but only a B- for execution. The moral of the story: Don't confront one of the best cars on the planet with a three-year-old chassis.