The wealthy can now drive with a clear conscious. And from the comfort of a leather-wrapped cabin.

Following the commercial success of the Toyota Prius hybrid and the Honda Civic Hybrid, Lexus is launching the first luxury SUV with hybrid power, the RX 400h.

Based on the RX 330, which is the best-selling luxury SUV on the market, the all-wheel-drive RX 400h uses a new hybrid system that combines the standard 3.3-liter V6 engine with two high-torque electric motor-generators. The benefits are the best fuel mileage in the SUV category, lower emissions and increased horsepower.

The 400h is certified as a Super Ultra Low Emission vehicle and boasts 268 hp. That's 38 more horsepower than the RX 330 and according to Lexus it's a power rating more typical of a 4.0-liter V8 engine, hence the 400h moniker.

Lexus also says the 400h accelerates from 0-to-60-mph in 7.3 seconds, which is as quick as the Mercedes-Benz ML500 and quicker than the 330. We noticed the increased power immediately.

The 400h's drive system is mated to a continuously variable transmission (CVT) instead of the five-speed automatic in the RX 330. It works well, but the truck's entire powertrain becomes loud when climbing slight grades at low speeds, which Lexus engineers tell us is characteristic of the CVT-hybrid relationship. Otherwise, the RX 400h drives surprisingly like the RX 330, which we've always liked.

Typically, the 400h starts up under electric power until the computer deems it necessary for the engine to fire up. This makes for quiet takeoffs, but it also highlights other noises that could be intrusive. To ensure a serene driving experience, Lexus added an acoustic glass windshield and a quieter radiator cooling fan. It also added electric power steering and electric air conditioning, so those systems can run prior to the engine kicking in.

The battery pack, which is the heart of the hybrid system, is under the 400h's rear seat. With 30 modules comprised of eight cells per module its total peak power is 80-percent stronger than the Prius's, which has six cells per module. Plus, it's packed into a new metal case for improved heat rejection and reduced size. So it wouldn't disrupt the truck's 40/20/40-split rear-seat configuration, the pack's been split into three groups and its height has been reduced by 22 percent over the Prius's.

Another new piece of technology introduced in the 400h is an all-encompassing vehicle stability control system Lexus calls Vehicle Dynamic Integrated Management (VDIM). Instead of reacting to an already occurring driving situation, VDIM is designed to anticipate vehicle instability in every direction while making stabilizing corrections.

The visual differences between the 400h and the RX 330 are minimal. Its tire fairings and underbody covers are unique to maintain an optimal 0.35 coefficient of drag, which is important for fuel economy, and the truck wears a reshaped front bumper, a new grille and LED combination taillights. The standard 18-inch aluminum wheels are also unique to the 400h, which weighs 300 pounds more due to the hybrid equipment.

Inside, there's brushed aluminum trim for a high-tech feel, and an illuminated power meter that displays the current hybrid powertrain information. If you opt for the available voice-recognition navigation system, the gas-electric power distribution is not only displayed on the small meter in the gauge cluster, but also appears on the multi-information display's seven-inch touchscreen navigation display just like in the Prius. The RX 400h also picks up some of the RX 330's options as standard equipment, including high-intensity discharge headlamps and a power rear liftgate. Pricing on the RX 400h is expected to start $4,000-$5000 higher than the RX 330.

Because the RX 400h has already secured more prelaunch orders than any other Lexus in history, the company is taking extra care to accommodate its customers. In September 2004, it announced a dedicated customer communication system that corresponds directly with the wait-list customers, updating them every few months on the status of their order. This retail ordering system allows dealers to assign a customer's name to a specific vehicle prior to production, and then track it through the distribution process. It also prevents buyers from hanging out on multiple order lists, trying to score the first-available vehicle from several different dealers.

And if you're concerned about your current Lexus lease agreement expiring while you're waiting for your chance to make luxury hybrid history in your neighborhood, don't worry. Lexus will also be extending current leases by as much as 12 months to aid customers on the 400h order list. The RX 400h is expected to arrive in early spring 2005.