Sound quality is not as great as other systems we've tested with this many speakers. The presence of three speakers on the dash, including one center fill, makes for an immersive audio experience, but a heavy bass note dominates the output even with the EQ setting for the bass turned way down. The thrumming bass is most evident at high volumes, where highs also tend to become shrill.
In addition to the standard audio system, our test car came with extra media playback capability with the inclusion of Infiniti's optional DVD mobile entertainment system ($1,400), which comes with two sets of wireless headphones (as a sophisticated safety feature, the headphones do not work in the front seats). To take their minds off the cramped seating arrangement, rear-seat passengers can watch DVDs on the system's 7-inch ceiling-mounted display. Discs are inserted into a slot in the DVD console near the floor, and those in back get full control, courtesy of a dedicated remote. Unlike the system in the M35 Sport, however, the rear-seat screen in the FX45 cannot be used to view or program the car's navigation system.
Other cabin tech in the FX45 includes an as-standard Bluetooth hands-free calling interface. As we have found with other Nissan and Infiniti models, the cell phone pairing process for the Bluetooth system, which is done entirely by voice command, is trickier than it should be, and we had to try repeatedly to get the system to recognize our phone. When the car and phone were paired, however, voice dialing was straightforward, with the system able to understand our spoken numbers and commands without any trouble.
Under the hood
As its name suggests, the FX45 boasts Infiniti's 4.5-liter V-8 engine, making 320 horsepower and a stout 335 pound-feet of torque. These vital statistics translate into a brisk driving experience as the hefty FX45 responds quickly to throttle inputs, especially when driven in manual shift mode, which uses downshift rev-matching to eliminate lurches between ratios.
Sharing its platform with the M35 coupe/ sedan, the all-wheel drive FX45 displays impeccable road manners around town and on the freeway, with responsive steering and handling that belies its 4,488-pound curb weight.
As part of its $4,200 Technology Package, our tester came with Intelligent Cruise Control (lCC) and a Lane Departure Warning (LDW) system. LDW works by mounting two range-finding CMOS cameras, which constantly monitor road markings, on the underside of each of the car's wing mirrors. If the car starts to change lanes by drifting over a lane dividing line, a light turns on in the instrument cluster, and a chime sounds in the cabin to let the driver know. On the FX45, the system only kicks in when the car is traveling at more than 45mph and is overridden if the turn signal is activated as the driver has declared an intention to change lanes.
While the LDW system attempted to prevent us from lateral deviations on the freeway, ICC ensured that we didn't rear-end the cars ahead. Using forward-looking radar sensors, ICC enables drivers to select a preset speed and then drive either at that speed or at a slower speed while maintaining a constant distance from the car ahead. In practice, driving the FX45 with ICC was an eerie experience as the car accelerated and decelerated of its own accord.
In our week with the FX45, we covered around 170 miles in mixed city and highway driving. Pressing the trip button, we were able to see that we achieved an average fuel economy of 15.5 miles per gallon--within the EPA's estimates for the car of 14mpg in the city and 18mpg on the highway, but conspicuously low for a vehicle in the crossover segment.
The 2007 FX45 will appeal to those looking for a luxury SUV with an edge in both styling and performance, although the latter comes at the expense of poor fuel economy. There are few crossover SUVs that offer as many cabin gadgets and driver-assist features as a fully optioned-up FX45. Our test car had a base price of $49,850, to which was added $4,200 for the Technology Package (navigation, LDW, ICC, Sirius Satellite Radio prewiring); $1,400 for the rear-seat entertainment system; $350 for aluminum roof rail cross bars; $70 for a cargo area protector; and $700 for delivery--adding up to a grand total of $56,570. While its technology features are still enough to set it apart from most luxury SUVs, Infiniti will need to make some upgrades (with a voice-command system and real-time traffic for its navigation system, for example) if it is to remain competitive with other high-tech models, such as the 2007 Lexus RX 350 and the 2007 Acura RDX.