Choosing between the GS 300 and GS 430 largely comes down to the value you place on performance. Speed costs money, how fast do you want to go? In this case, shaving two seconds off your 0-60 times costs approximately $9,100. That's a big difference in dollars, but it's a huge difference in performance. The GS 430 accelerates much more quickly than the GS 300. Plus the GS 430 comes with a higher level of equipment than the GS 300 does.

Like BMW, Lexus uses an inline-6 for the GS 300, and enthusiasts tend to prefer inline six-cylinder engines over the more popular V6 configuration (which costs less to build and takes up less space). Its design tends to make the inline-6 inherently smoother than a V6, and the inline-6 used in the GS 300 is a wonderful engine. It purrs like a kitten and we think it's smoother than the six-cylinder engines from BMW and Mercedes. The 3.0-liter engine produces 220 horsepower. Lexus claims it can propel the GS 300 from 0 to 60 mph in 7.8 seconds and through the quarter mile in 18.8 seconds. That's brisk performance, but don't expect to win many drag races. It earns an 18/25 mpg City/Highway rating from the EPA, which is average for the class.

The GS 430 can accelerate from 0 to 60 mph in 5.8 seconds, according to Lexus, putting it in a league with some of the world's best sports sedans. The GS 430 practically leaps off the road when you floor it, and surges with seemingly unlimited power as it passes other vehicles on the highway. Yet its sound is subtle, a high-tech mechanical note rather than the angry racket of a Corvette's V8. The 4.3-liter V8 produces 300 horsepower and 325 pound-feet of torque. Strong low-rpm torque gives the GS 430 plenty of around-town cruising power, and allows it to sprint away from intersections. Lexus says it can turn the quarter mile in 14.2 seconds. It's a sophisticated engine with four camshafts, 32 valves, and variable valve timing, which allows it to deliver strong torque at low engine speeds, while providing healthy horsepower at higher speeds. In spite of its impressive acceleration, the GS 430 earns an EPA Highway rating of 23 mpg and is certified as an Ultra Low Emissions Vehicle (ULEV).

All Lexus GS sedans come with a five-speed electronically controlled automatic transmission and a console shifter. It's a smooth and responsive transmission. The GS 300 can also be shifted by using a set of buttons on the front and back of the steering wheel. Pushing the button on the front of the steering wheel downshifts one gear. Pushing the button behind the wheel upshifts one gear. A readout at the bottom of the speedometer displays the selected gear. Electronics prevent downshifting above the engine's redline.

Like all true high-performance cars, the Lexus GS uses rear-wheel drive. Under normal driving conditions, the GS is smooth and effortless. This is no marshmallow, but the ride quality is smooth. The suspension absorbs road variations, while providing reassurance in tight turns and fast sweepers. The steering requires enough effort to instill that firm feeling of control often missing in luxury cars.

Big, high-performance brakes bring the GS to a halt quickly and without drama. Anti-lock brakes (ABS) with Brake Assist, electronic traction control, and Vehicle Stability Control are standard. Brake Assist can sense when the driver is in a panic braking situation and will automatically maintain full braking power, even if the driver mistakenly relaxes pressure on the brake pedal. It's an excellent safety feature, as research has shown that many of us do not push the brake pedal as hard as we should in an emergency or relax pressure on the brake pedal when we feel the anti-lock brakes pulsing. Vehicle Stability Control monitors the car's direction versus the position of the steering wheel, and if they are not consistent with one another, provides light braking force to one or more individual wheels to correct the car's course. VSC can be switched off via a console-mounted button, though we recommend against doing this unless you're competing in an autocross.

Handling is excellent on winding roads. An optional Upgraded Tire Package ($215) boosts the GS 430's cornering with a set of 235/45ZR17 Bridgestone Potenza RE030 tires on 17-inch wheels. However, the standard 225/55VR16 Michelins on 16-inch wheels stick just fine.

The GS 430 comes standard with high-intensity discharge headlamps, which throw a wide low-beam pattern with bright, sharply defined edges. These lights are optional on the GS 300 ($515). They work great when aimed properly but have drawn ire from some motorists.