Vehicle Overview
The full-size rear-wheel-drive Q45 serves as Infiniti's flagship sedan. A new Sport model with Rear Active Steer, a sport suspension and 19-inch wheels emerges for the 2006 season. Rear Active Steer adjusts rear-suspension geometry according to steering input and vehicle speed. A Bluetooth-based hands-free phone system is standard, and Infiniti's Lane Departure Warning system has been added to the available Premium Package. The modified five-speed-automatic transmission has wider gear spacing and rev matching.

For 2005, the Q45 adopted new front and rear fascias, a restyled hood and grille, new headlights and a different deck lid. LED taillamps are installed, and the body is adorned with chrome trim.

The heated mirrors have a memory function and a selectable tilt-down feature when in Reverse gear. The trunk lid can open and close automatically.

The Q45's seven-lens high-intensity-discharge headlights are among the most powerful installed in a passenger car. Alloy wheels hold 17-inch tires on the base model; titanium-finish 19-inch wheels are mounted on the Sport sedan. A tire-pressure-monitoring system is standard, and run-flat tires are optional. Built on a 113-inch wheelbase, the Q45 is 200.8 inches long overall, 58.7 inches tall and 72.6 inches wide.

The Q45 seats five occupants. Sport contour double-stitched seats, a pure white gauge cluster and a metal gearshift bezel are installed. Dark maple wood and chrome accents decorate the interior. The DVD-based navigation system has a 7-inch screen and a RearView Monitor that provides a view of the area behind the car when backing up.

Heated front seats are standard; cooled seats are optional. Power heated rear seats are included in a Premium Package. The 300-watt Bose audio system has eight speakers, an in-dash six-CD changer and a cassette player. Either XM or Sirius Satellite Radio is available. A power rear-window sunshade and manual rear-door window sunshades can be installed. Intelligent cruise control with preview braking is also available.

Under the Hood
Infiniti's 4.5-liter V-8 develops 340 horsepower and 333 pounds-feet of torque. It works with a five-speed-automatic transmission that has a manual-shift provision.

Antilock brakes have vented discs all around. The brakes feature electronic brake-force distribution and brake assist that can help in emergency braking. Seat-mounted side-impact airbags and side curtain-type airbags are standard. Front "pre-crash" seat belts tighten during emergency braking. The front seats have active head restraints. Infiniti's Vehicle Dynamic Control electronic stability system is installed.