Infiniti, Nissan's premium brand, makes two sedans, the G and M series. The M is the larger, more expensive sedan, and is available as the M35 and the M45, the numbers signifying engine displacement. The M45x also has all-wheel-drive.
The engine in the M45x is a 4.5-liter V-8 producing 325 horsepower and 336 foot-pounds of torque. It is not extraordinarily powerful, but it gets the job done. Our testing showed fuel economy of a little better than 16 mpg, about what you would expect from this engine.
The steering wheel controls are nicely blended into the material, with audio controls on the left and cruise control on the right. There is also a button on the lower right to turn on Lane Departure Prevention, a unique system that nudges the car back into its lane if it starts drifting into another.
Infiniti's interface is very usable. The main knob has buttons inset on top that help navigate around screens. The LCD is also a touch screen, although it is a little far from the driver, and there is voice command.
The navigation system includes XM NavTraffic. The green line on one side of the freeway indicates free flowing traffic, while the amber line on the other side shows traffic traveling between 20 and 40 mph.