Infiniti calls its redesigned 2009 FX50 a "radical expression of sport and utility," and while we're generally skeptical of marketing catchphrases, this one's pretty accurate. The FX50 is Infiniti's top-of-the-line crossover, replacing the outgoing FX45, which debuted along with its FX35 sibling in 2003 as one of the first crossovers to include high performance and showcar style in its portfolio. Designed as a kind of personalized coupe with four doors and extra cargo capacity, the FX45 showcased some segment-leading technology and delivered acceleration and handling on par with the sportiest European-brand crossover SUVs.

The original V8-powered FX45 never quite caught on with buyers, however, partially because it didn't offer much additional power over the V6-powered FX35. So Infiniti is trying again with the FX50. The name change reflects the increased size of the new 390-horsepower 5.0-liter V8, which replaces the previous 320-hp 4.5-liter V8. This translates into serious straight-line acceleration -- try zero to 60 mph in 5.6 seconds.

All that giddyap is gracefully tamed by a new seven-speed transmission, as well as standard all-wheel drive. If you can live with the premium fuel bills, the FX50 supplies just about all the driving thrills that relatively affluent family men and women could want. Should you find the V8 to be a bit much, Infiniti has also redesigned the FX50s little brother, the V6-powered FX35.

The FX50 is built on Infiniti's latest version of its FM platform (the same one that underpins a variety of products, including the G-series and M-series cars) and is said to be considerably stiffer than before. These changes, along with an improved suspension with available adaptive dampers and active rear steering, deliver nimble, confident handling.

Regrettably, when it comes to the exterior of the 2009 FX50, the designers haven't adhered to quite the same exalted standard as the engineers. The new look is certainly distinctive, but some object that the gaping grille gives the car an unpleasant fishlike look. Moreover, form often trumps function -- the FX50's styling has been contrived in such a way that its swept-back form actually reduces the previous model's already limited cargo capacity.

On the positive side, the 2009 Infiniti FX50 boasts a gorgeous new interior that's crammed with inviting interfaces and a bevy of former options that are now standard. Driver and passengers are cradled in diamond-quilted leather seats. Chrome and brushed-metal accents tastefully adorn the instrument panel and frame the other control surfaces. Suffer from allergies? The FX50's climate-control system has you covered, with an advanced air purifier and allergen-neutralizing filter. There's also a new hard-drive-based navigation system and a bevy of safety features, including active braking and an advanced lane-departure warning system.

Overall, we think the 2009 Infiniti FX50 is a worthy, if still idiosyncratic, extension of its crossover SUV legacy. It's almost in a class of its own -- BMW's X6 is the only other luxury crossover that unapologetically prioritizes style and performance over utility. For better or worse, the FX50 also carries on the tradition of looking like nothing else on the road (other than the first-generation FX crossovers, that is). If you're drawn to a luxury crossover that has always had a distinctive identity, then we suppose standing out from the crowd is part of the fun.

The 2009 Infiniti FX50 is a five-passenger midsize luxury crossover SUV. It comes standard with 21-inch alloy wheels, bi-xenon headlights, a power liftgate, a sunroof, a tilt/telescoping steering wheel, heated and cooled power front seats with driver memory settings, leather upholstery, dual-zone automatic climate control with a filtration system, a hard-drive-based navigation system and a full-view parking monitor. Also standard is an 11-speaker Bose audio system with a CD/MP3 player, satellite radio, Bluetooth, digital music storage capability on the hard drive and iPod integration.

An optional Sport Package adds adaptive front headlights, active rear steering, adaptive dampers and sport front seats. The Technology Package includes an advanced lane-departure warning system, adaptive cruise control with enhanced capabilities in congested traffic, Intelligent Brake Assist and rain-sensing front wipers. A rear-seat entertainment system and an exterior styling kit are also available.

Under the FX50's hood is a 5.0-liter V8 that makes 390 hp and 369 pound-feet of torque. Power is sent to all four wheels through a seven-speed automatic transmission with manual shift control and rev-matched downshift capability. Infiniti estimates that fuel economy for this engine is 14 mpg city/20 mpg highway.

Antilock disc brakes with brake assist, front-seat-mounted side airbags, full-length side curtain airbags, traction control and stability control are all standard on the 2009 Infiniti FX50. This year sees the addition of other safety technology, including an advanced lane-departure warning system that can help prevent the vehicle from inadvertently traveling out of its intended lane. The new Intelligent Brake Assist (IBA) uses the laser range finder from the adaptive cruise control to analyze closing speeds to an obstacle ahead. If a forward collision is imminent, the system sounds a warning to prompt driver action and can automatically apply the brakes up to 0.5g.

In National Highway Traffic Safety Administration crash tests, the FX scored five (out of five) stars for its protection of occupants in both front and side impacts, and in Insurance Institute for Highway Safety frontal-offset testing, the FX earned the top score of "Good."

Speed is the 2009 Infiniti FX50's prime directive. With its new seven-speed automatic clicking off admirably quick upshifts, there's hardly a moment when the FX50 doesn't feel geared up for action. The 60-mph mark flashes by in just 5.6 seconds, as compared to the 6.8 seconds required for the FX45's 60-mph sprint. Moreover, when the tach needle sweeps past 4,000 rpm, there is a conspicuous surge of power from the FX50's V8, courtesy of its sophisticated system for variable valve timing and lift.

On a twisty road, the FX50 handles like a sport wagon, negotiating turns quicker than one would expect. There is one significant caveat, however. During our instrumented testing regimen, we detected an unusual amount of brake fade after several high-speed passes. However, it should be noted that when subjected to brake testing that more closely mirrored the real world, brake fade wasn't an issue for our test vehicle.

Read our 2009 Infiniti FX50 Long-Term 20,000-Mile Test

The 2009 Infiniti FX50 has a comfortable, well-appointed cabin befitting a luxury crossover SUV. The use of chrome and brushed-metal accents is restrained and tasteful, as is the deployment of hand-stained maple wood trim. A host of standard features, along with optional entertainment configurations, provides passengers with ample entertainment possibilities and equips the driver with comprehensive navigation tools and long-haul labor-savers. Rear legroom is diminished compared with the 2008 model, as is cargo capacity. There are fewer than 25 cubic feet available with the rear seat up, growing to only 62 cubic feet with the rear seat folded down. Most midsize crossovers offer considerably more cargo volume.