The Good: A punchy V-6 gives the 2007 RX 350 sedanlike performance. Lexus's usual luxury fixtures comes as standard, and options include GPS navigation, Bluetooth, and a rear-seat entertainment system. The Bad: The 2WD RX 350 is prone to loss of traction on more-challenging terrains. The Bottom Line: The Lexus RX 350 is a luxury SUV that delivers a stylish, sporty ride. A powerful--and relatively economical--engine endows Lexus's flagship truck with solid performance, although the AWD version is recommended for anything away from the asphalt. A collection of optional cabin tech makes the RX 350 a wired ride. Lexus has had a hit on its hands with the RX series ever since the introduction of the RX 300 in 1999, followed by the more-powerful RX 330 in 2003. The release of the RX 350 for the 2007 model year brings yet another performance upgrade to its top-selling car-based SUV line, with the inclusion of a 3.5-liter V-6 engine, capable of producing 270 horsepower. The RX 350's upgraded power plant and advanced driver-assist systems, combined with the car's distinctive, aerodynamic form, give it performance credentials more in line with a crossover than with a full-size SUV. Throttle control is sharp and steering is responsive, although standard suspension is tuned more for highways and parking lots than off-road trails. Our tester came with the Performance Package ($4,955), which includes four-wheel air suspension, sequential automatic transmission, and adaptive front lighting. While its enhanced performance will grab the notice of luxury sedan owners with growing families, the RX 350 comes with all of the standard appointments and safety features one would expect on an upscale SUV: leather- and wood-trimmed interior, a decent standard audio system with a six-disc in-dash changer, and automatic controls for everything from the heated outside mirrors to the rear tailgate. \u00c0 la carte options on the RX 350 include Lexus's fifth-generation voice-activated GPS satellite navigation system with an integrated backup camera, Bluetooth hands-free calling ($2,650), and a rear-seat entertainment system ($1,740). An upgraded Mark Levinson stereo system is available only as part of a package that includes navigation, Bluetooth, and performance upgrades, for $6,190. Without any of the major information\/entertainment options, our tester based at $37,400; with the performance package, which includes optional multistage heated front seats ($540), a $92 cargo mat, and a delivery fee of $695, it leaves the lot for $43,682. Our RX 350 was decked out with the usual Lexus cabin luxury in the shape of ivory-leather trim with (imaginatively named) golden bird's-eye maple accents. The driving position in the RX 350 offers a commanding view of the road, and there is ample legroom and headroom for taller passengers, both in front and in the back. The RX 350's cargo space of 84.7 cubic feet is respectable for a car-based SUV and is maximized by the folding, 40\/20\/40-split rear seats, which can slide forward and backward depending on passenger or cargo priorities. Cargo space in the RX 350 is maximized by the folding, split-rear seats. Rear visibility is somewhat hindered, however, by the RX 350's raked roofline and wide C-pillars. Up front, 10-way power seats with optional heating and ventilation as well as dual-zone climate control keep the driver and the front passenger in their comfort zone. Our test car also came with a power tilt\/telescoping steering wheel with memory as part of the Performance Package. Unfortunately, the test model did not come with many of the optional gadgets that would differentiate the RX 350 from lesser SUVs. Most conspicuously, it did without Lexus's fifth-generation navigation unit, which so impressed us in the 2006 Lexus IS 350. Navigation, along with a backup camera and a Bluetooth hands-free interface, is available for an additional $2,650 or as part of the Luxury Value Edition package, which also includes an upgraded 11-speaker 210-watt audio system from Mark Levinson. This upgraded system needs to be outstanding if it is to justify an upgrade from the RX 350's standard satellite-ready, MP3- and WMA-compatible AM\/FM\/CD audio system with a six-disc in-dash changer, which we found to be by far the most impressive feature of our admittedly low-tech tester. While the display of ID3-tag information for MP3 and WMA CDs is limited to a single, truncated line of text, sound quality through the six speakers is excellent for a standard system. Incorporating an Automatic Sound Levelizer (ASL) and a digital sound processor, the audio system delivers clean bass and clear separation across a range of music genres, and audio clarity is enhanced by the RX 350's inclusion of vibration-canceling engine mounts. While it displays only one truncated line of ID3-tag information, the standard audio system produces good sound quality. The other major entertainment option available on the RX 350 is the rear-seat DVD entertainment system with the roof-mounted LCD and wireless headphones that we saw in the 2006 RX 400h, and which comes with a 9-inch screen--2 inches bigger than that in the RX 330. Also available--but not featured in our model--is adaptive (or in Lexus-speak, Dynamic Laser) cruise control to enable drivers to electronically maintain a preset distance while following vehicles on the highway. The only significant external difference between the RX 350 and the outgoing RX 330 (the car it replaces) is the addition of a grille below the front bumper. The 3.5-liter V-6 RX 350 is more powerful than the Lexus RX 330, generating a healthy 270 horsepower, which is enough to propel the 4,090-pound RX 350 from standing to 60mph in 7.3 seconds. Engine tech is also upgraded in the RX 350, which uses dual variable-valve timing to optimize performance and reduce emissions. With the Performance Package, the RX 350's 5-speed automatic gearbox includes sequential transmission. The five-door RX 350 is technically an SUV, but it is cut from different cloth than truck-based models. While calling it nimble is a stretch, its throttle response is good, and its handling and road-holding when thrown into corners is more akin to a car than a truck. In keeping with its driving-to-the-country-club, luxury-SUV persona, the standard MacPherson strut suspension is supple with excellent damping. Our 2WD tester came with a Performance Package, which equipped it with four-wheel air suspension for driving in different conditions. At speeds of over 62mph, the RX 350 automatically lowers by 0.3 inches to increase handling and reduce the car's drag coefficient. Those wishing to get even sportier can press a button to lower the suspension a further 0.3 inches. There are also options to lower the car still further for ease of access or loading and to increase suspension height for off-road driving. The RX 350 features four-wheel air suspension which can be raised for off-road terrain... ...or lowered for sportier driving or cruising on the highway. Despite being equipped with variable stability control, our front-wheel-drive version had a habit of losing its grip and wheel-spinning on challenging inclines. That minority of drivers investing in the Performance Package for off-track use should also consider upgrading to the AWD model, which provides a 50\/50 front-to-rear power split and adds a viscous, limited-slip, center-differential transfer torque to those wheels with the most grip when driving in off-road situations. The RX 350 is remarkably economical for a V-6 SUV. According to the EPA, it will get 20mpg in the city and 25mpg on the highway. In our experience of city-weighted mixed driving, we observed an average of 21.6mpg, which is extremely respectable for a car of this power and weight. Thanks to its emissions-reducing engine technology, the RX 350 retains the RX 330's Ultra-Low Emission Vehicle II (U-LEV II) certification, despite being more powerful. Safety features on the RX 350 are plentiful and in line with Lexus's reputation. Four-wheel antilock brakes with brake assist and electronic brake-force distribution come as standard, as do vehicle stability control and a tire pressure-monitoring system. Also standard are dual advanced front airbags, driver's knee airbags, front and rear side-curtain airbags, and front-seat-mounted side airbags. As part of its Performance Package, our test model came with high-intensity discharge headlamps with Lexus's adaptive front lighting system, enabling the headlights to swivel to correspond to the direction of the vehicle when turning, and rain-sensing wipers. The RX 350 comes with Lexus's new vehicle limited warranty, which includes four-year\/50,000-mile basic coverage, six-year\/70,000-mile powertrain coverage, and six-year\/unlimited mileage corrosion coverage. Lexus also provides the vehicle's first scheduled maintenance service for free.