The issue, at least at first, will be to convince people this really is a new vehicle. In photos, it looks so much like its big brother that people might not realize it's supposed to be a different kind of drive. Next will come the small matter of getting people used to the idea of a high-performance Land Rover--that's high performance as in smokin' 'em on the switchbacks, not casually tip-toeing along a rock-strewn mountain trail.

The new Range Rover Sport is Land Rover's first shot at the burgeoning fast-SUV market. To ensure the Sport is what it says it is, the top-of-the-range version boasts a Jaguar-sourced supercharged V-8 underhood kicking out 390 horsepower (the entry-level model gets the same 300-horse, 4.4-liter naturally aspirated version of the engine as used in the LR3). Land Rover is clearly targeting the BMW X5 for pavement athleticism, but claims far more off-road ability. The RRS's top speed is pegged electronically at 140 mph, the limit of off-road-tire technology. And yet, with extensive use of electronics and clever suspension hardware, as well as such traditional SUV items as a low-ratio transfer box, Land Rover claims the Sport can reconfigure itself at the flick of a couple of switches from fast-road handler to trailer hauler to serious off-road explorer.

Despite its nameplate, the Sport is derived from the all-new, SUOTY-winning Land Rover LR3, a completely different bloodline from the Range Rover's. But the Sport is a lot more road-focused than the LR3, or indeed the Range Rover itself, because of important changes to the hardware and, as you'd expect in 2005, to some influential software.

Hardware first. Compared with the LR3, the Sport's wheelbase is nearly six inches shorter at 108 inches. It's a strict five-seater, with no third row. It also rides lower on its suspension, though the system is similar: control arms all around, with air springs and self-leveling. It runs bigger, lower-profile tires.

The supercharged version gets a system called Dynamic Response, a powered anti-roll bar that actively resists cornering sway. Cutting the roll is vital to a sporting drive: It means faster steering response and more precision as well as extra grip because the tires are kept more upright.

Dynamic response means stiff anti-roll bars when you need them, not when you don't, and it's a more elegant solution than simply fitting bigger anti-roll bars, which makes for a disturbed straight-line ride, as the BMW X5 proves. Compared with the LR3, the RRS's suspension pickup points have been moved to raise the roll center. The Sport also has a variable-rate power-steering system, which means the steering can be sharp in corners without being twitchy at speed in a straight line. The supercharged version also gets significantly upsized four-pot Brembo brakes.