Lexus is known for smooth ride and luxury appointments, and the GS has accomplished road manners. Its fundamental sense of balance makes driving enjoyable. Even during a morning commute, you can seize a few moments of driving enjoyment.

The available 18-inch tires can make the ride a bit harsh, however. In our test of a GS 460 on Chicago streets, the suspension reacted harshly to sharp potholes, sending the types of sounds into the cabin that make you feel like you're in danger of popping a tire or doing suspension damage.

The GS can rip down the road if you like. Wide tires furnish plenty of cornering grip: P245/40ZR18 tires are standard equipment for both the GS 450h and GS 460, while the GS 350 carries P225/50WR17 tires.

The base suspension geometry provides good handling, while gas-charged dampers and coil springs promote a resilient, long-legged ride. The GS 450h and GS 460 both have two-position, electronically adjustable damping control to help the car adapt to driving conditions, as well as available Power Active Vehicle Stabilizer, which minimizes body roll during fast driving and further enhances the sensation of effortless speed.

The high-tech electric power steering is exceptionally sophisticated. Its Variable Gear Ratio Steering reduces the amount of steering lock (not just steering effort) at very low speeds and accelerates the steering effect as the wheel approaches full lock. The system matches wheel angle to the speed at which the driver is turning the steering wheel in order to offset any delay in the car's response to steering input. This works especially well on winding roads. A correction feature offsets the effects of crosswinds, making small steering adjustments automatically.

The steering system makes it possible to manage a powerful, rear-wheel-drive car in all kinds of driving and (more important) all kinds of weather. But we felt that both the electric power steering and electric brake system occasionally deliver an unnatural feel through the controls. During ordinary driving, we adapted quickly, but the combination of these electric systems with VDIM proved faintly distracting during enthusiastic driving. In fact, the hybrid GS 450h actually annoyed us because the transition from conventional friction braking to hybrid-style regenerative electrical braking frequently proved clumsy and unpredictable.

Overall, the heavy, 4134-pound GS 450h is the quickest of the GS sedans, getting to 60 mph in 5.2 seconds, though it's capable of just 131 mph. The 3945-pound GS 460 launches to 60 mph in 5.4 seconds on the way to a top speed of 149 mph, and the 3795-pound GS 350 sprints to 60 mph in an impressive 5.7 seconds (5.8 seconds for AWD) on its way to a top speed of 143 mph.

Fuel economy for the GS 450h is rated 22/25 mpg City/Highway on the government's EPA cycle. The GS 460 is rated 17/24 mpg, the GS 350 gets 19/27 and the GS 350 AWD is rated at 18/25.

In our opinion, the GS 350 is more enjoyable to drive than its up-market siblings. The V6 is responsive and just plain fast. The gear changes of both the six-speed automatic transmission are virtually undetectable. The GS is not the sort of car that encourages manual shifting, but it is a performance car, and the feeling of acceleration is a large part of its appeal.

Conventional steering and braking helps the GS 350 feel more natural than the more-expensive models with all their drive-by-wire technology. The 17-inch wheels provide the best ride quality and the 18-inch tires are available to provide more cornering grip for drivers who feel they need it. In particular, the all-wheel-drive model feels surprisingly alert and maneuverable thanks to its rear-biased power delivery.

The GS 350 gives up some dynamic control at the outer limits of its performance envelope compared to the GS 450h and GS 460, but it's more enjoyable to drive at conventional speed. The all-wheel-drive version of the GS 350 copes with a wide range of weather conditions and doesn't seem to offer many compromises in terms of speed, handling or even fuel economy.

Lexus has at least partially solved a problem with the new-for-2008 GS 460. The 2007 GS 430 was priced almost as high as the hybrid, but was not appreciably faster than the V6, and it got the worst fuel economy of the bunch.

The new 4.6-liter V8 on the new GS 460 is a paragon of responsiveness, providing ready power from a stop that makes it seem even faster than it is. While the GS 460 is slower in a sprint than the GS 450h, the V8 seems to provide more willing power at midrange and highway speeds. We did find, however, that the eight-speed requires a deep stab of the throttle to coax the downshifts needed for maximum passing punch.

The GS 450h uses the same 3.5-liter V6 as the GS 350, but it is teamed with two electric motors to produce an equivalent 340 horsepower. The GS450h's powertrain is a technological marvel. The gas engine doesn't start until it's needed, and it shuts off at stoplights, so the car can be on and the engine off. The electric motors are capable of powering the car at low speeds. The powertrain is more impressive, though, when you stomp the throttle and find it's faster than Lexus's impressive new V8. The smooth CVT will leave many drivers missing the rewarding climb through the gears of a conventional automatic, but using the manual shift mode with its six preset gear ratios can remedy that.

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