In just five years, vehicles with hybrid technology have gone from small and under-powered to large and over-priced.

The new 2006 Lexus RX 400h is a luxurious, functional, environmentally positive vehicle.

It has more amenities, gets better gas mileage and even goes faster than the traditional, gasoline-only RX 330 sport-utility that serves as its foundation.

But that vehicle costs $36,675 when it’s configured as a two-wheel-drive SUV and $38,075 as an all-wheel-drive model. The hybrid gas-electric version, being sold as a 2006 model, goes for $49,185 in its AWD, everything-but-the-kitchen-sink setup.

Toyota, the maker of this upscale Lexus machine, points out that it has standardized features on the 400h that are options on the 330 — “more than $6,000” worth.

That’s clever marketing. The fact remains that if you want a hybrid Lexus SUV you have to take all this other stuff, too. And you’ll pay more than $11,000 more for an RX 400h than for an RX 330.

But Lexus insists — and customer pre-orders seem to bear out — that demand exists for an upscale, green SUV. And the Lexus RX 400h is the first and only choice for this buyer.

Three other hybrid SUVs, the Toyota Highlander, Ford Escape and Mercury Mariner, are, in comparison, downscale choices. Nice enough, and better bargains, to be sure, but nothing that approaches the Lexus look and feel.

And, my ravings aside, the RX 400h is a top-notch machine.

Inside, you’ll find soft leather seats for five, an incredibly nice stereo (a $980 Mark Levinson unit), a sunroof, leather seats, automatic air conditioning and more. Safety equipment includes seven air bags, all sorts of helpful braking assistance and an integrated stability system.

The whole thing isn’t much of a stretch from the basic RX 330, the vehicle that in large part confirmed the luxury-cross-over-utility boom and still dominates the segment.

Lexus points out subtle differences between the 330 and the 400h. The hybrid gets a different grille, special 18-inch wheels, aluminum instead of wood interior trim and a special suspension tuning to handle the car’s extra weight.

The primary difference between the 330 and the 400h is how the hybrid works.

It uses a similar 3.3-liter V-6, but with some revisions to put it in sync with Toyota’s hybrid system. It includes a 288-volt DC nickel-metal-hydride battery pack, situated under the rear seat. A converter switches power to AC.

The reason Lexus can claim the new hybrid RX is more powerful than the gas version is its three motor-generators. They work as both drive motors and generators. One serves as a starter for the gas engine and controls transmission speed. Another distributes power to the wheels through the vehicle’s continuously variable transmission. The third works to boost power via the all-wheel-drive system.

In total, Lexus says, the RX 400h makes 268 horsepower and goes from 0 to 60 mph in 7.3 seconds. The RX 330 makes 230 horsepower, and needs an extra half-second to reach 60 mph.

Behind the wheel, the experience isn’t strange or bewildering, but it does take a bit of driving to get used to it. The engine on/off function, one of the main reasons that city mileage exceeds highway, means a slight shudder when stopping and starting. It also means an extremely quiet vehicle when you’re stopped at red lights and stop signs.

At 4,365 pounds, the 400h is 300 pounds heavier than the 330. The result is a vehicle that, while very comfortable and suitable on the road, doesn’t feel much like a sportier SUV such as a BMW X5.

Instead, it’s an upscale family hauler, a perfect choice for those with kids playing soccer in the nice suburbs.

Besides the price, the only other number that potential buyers care about is fuel economy. Lexus says the RX 400h gets 31 mpg in city driving and 27 on the highway. In a mix of both over several hundred miles, I got about 28 mpg. (The gas-only AWD RX 330 gets 18 and 24 mpg in city and highway driving).

The number of available hybrid models has tripled since 2003, the Automotive Information Center reported this week, and many more are coming. But, for now, the tiny Honda Insight grabs the highest-mileage spot, the Toyota Prius defines the coming of age of hybrid technology and the Lexus RX 400h confirms that a market exists for those with green sensibilities and plenty of green in their wallets, too.

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Talk to Matt Nauman about new cars online for a live question-and- answer session from noon to 1 p.m. today at www.mercurynews.com . You also can contact him at mnauman@mercurynews.com or (408) 920-5701.