The M45 builds on Infiniti's M35 sports sedan, but adds a potent 325 horsepower 4.5-liter V8 as the main difference, out-powering the six cylinder-powered car by 23 hp.

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Standard equipment is similar to the M35 and includes an Intelligent Key with Push Button Ignition, Bluetooth hands-free phone system and 18-inch wheels.

New to the M45 model range for the 2008 model year is an optional all-wheel drive model -- dubbed the M45x. The AWD system has been available on the M35x in the past, but the 2008 model marks the first the system have been available on the V8-powered car.

An optional Sport package on the rear-wheel drive model adds Infiniti's Rear Active Steer system which turns the rear wheels slightly away from a turn to help the car round a bend, forklift-style. The package also includes uniquely styled 19-inch wheels that are also slightly wider and shod in bigger performance summer tires, a more aggressively tuned suspension, and more supportive front seats. The interior is otherwise changed thanks to a package-specific steering wheel and shifter, with aluminum trim on the console and on the pedals. From the outside, unique front and rear fascias identify the Sport package.

Technophiles might want to opt for the Technology Package, which comprises a Bose-tuned audio system with 8 speakers. The six-disc changer on the standard car is replaced with a single-slot player that integrates a 9.3GB Music Box hard drive that can store MP3 music files from the CD. A full iPod interface is also included. The hard drive also contains navigation data that is displayed via an 8-inch touchscreen display and comes with XM Nav Traffic live updates, though that requires a monthly subscription. The display is also a part of the RearView Monitor system that detects behind the car when reversing. The multi-talented system also features voice recognition to control audio, climate control and the navigation system functions.

The next step up is an Advanced Technology package which should appeal to audiophiles with its 14-speaker Bose surround system capable of digital 5.1-channel decoding and multimedia drive. Other techno goodies in the package involve active cruise control, as well as brake assist and lane departure active safety systems.

A ceiling-mounted DVD multimedia system for rear-seat passengers is another major option, and a Premium package combines all three. Detail additions such as a rear spoiler, wood interior trim, and polished wheels round out the options list on Infiniti's luxury flagship sedan.