You've heard the expression "don't mess with success." That adage could well have been applied to Lexus' best-selling RX 300. As the best-selling model in the Lexus lineup, the RX 300 was showing no signs of slowing down despite its advancing age. So it must have been with great caution that Lexus undertook the redesign of the RX in 2004 -- messing it up could have had dire financial consequences.

If ever there was a textbook definition of "improvement," the RX 330 has to be it. The latest Lexus RX 330 is sleeker, more powerful, roomier and has an even more luxurious interior than its well-regarded predecessor. Of course, the RX 330 still offers everything that made the previous Lexus SUV a sales success. The elevated seating position, forgiving ride and smooth drivetrain are still there, only more so.

While the original Lexus RX 300 offered plenty of luxury in an SUV package, the RX 330 ups the ante in terms of both luxury and performance. A full set of auto-dimming mirrors is standard on the RX 330 as are memory seats, a power front-passenger seat, steering wheel-mounted audio controls, four one-touch power windows, heated sideview mirrors and fore-and-aft-adjustable rear seat. A refined suspension and steering system return a comfortable ride while providing reasonable road feel and a tight turning radius. A major sticking point on the old RX 300 was the curious manner in which all the climate control and audio system functions were housed in one screen in vehicles equipped with a navigation system. The RX 330 has a much improved design as the stereo controls are now separate.

The RX 330 is a great example of what a luxury crossover utility can be. Excellent performance, a large interior and plenty of unique features make the Lexus SUV stand out in an already competitive segment. Even with new competitors cropping up at every turn, the 2006 Lexus RX 330 remains one of the best luxury SUVs on the market.

The Lexus RX 330 is available in a single trim with either front-wheel drive or all-wheel drive. The standard equipment list includes items such as power-adjustable front seats, stability and traction control, second-row seats that slide and recline, dual-zone automatic climate control and a power rear hatch. The options list is extensive, with most major components bundled together into packages. One package adds a navigation system along with a Mark Levinson audio system, while another adds 18-inch wheels and tires, a sport-tuned air suspension and leather upholstery. Notable options include HID headlights that swivel when you turn, a rear-mounted camera for seeing what's behind you while backing up, and a rear-seat DVD entertainment system with wireless headphones.

The Lexus RX 330 is powered by a 3.3-liter V6 rated at 223 horsepower and 238 pound-feet of torque. A five-speed automatic is standard, and Lexus sells the RX 330 as either a front-wheel-drive or all-wheel-drive model.

The Lexus RX 330 features standard front, side, head and even driver knee airbags. Standard stability and traction control systems also lend an added measure of active safety to the RX's considerable repertoire of safety devices. Frontal-impact crash testing conducted by the NHTSA resulted in a five-star rating (out of five) for the driver and four stars for the front passenger. The Lexus SUV also earned five stars for side-impact safety. The RX 330 received a "Good" rating in IIHS frontal-offset crash testing and was named a "Best Pick" for its class.

As expected, the 2006 Lexus RX 330 delivers all the smoothness and sophistication one would expect from Lexus. The V6 offers plenty of power and refinement, and the five-speed transmission handles it well. Occasionally, the five-speed seems to get confused, but its overall performance is solid. Due to the luxurious intent of the RX 330, handling is a little on the soft side with plenty of body lean when cornering; although, the vehicle never feels floaty or uncontrollable. Those seeking firmer handling should opt for the 18-inch wheels and air suspension.

Inside the RX 330, three round, chrome-rimmed gauges house the vital information, while an angular center pod tapering into an attractive center console houses the audio/nav system and climate control functions. Metallic-looking surfaces combined with rich wood really drive the RX's luxury theme home. Along with its sleek exterior, the RX 330's cabin presents a sporty, youthful look. There's also a 40/20/40-split rear seat that slides and reclines for maximum passenger comfort. In back, the RX offers 38.3 cubic feet of luggage space (85 cubes with the seats folded), as well as a standard power-operated liftgate.