With the hardtop raised and symphonic sound swirling through the leather-lined cabin, the SC 430 cruises in the insulated Lexus mode: quiet motoring supported by dazzling electronic wizardry and effortless controls.

Or stow the top, put your foot down, and feel the immediate response of 300 horses, as fresh air swirls around you. The SC 430 can rip down a straightaway at an illicit pace, or cut through off-camber mountain curves with the dexterity of an athletic sports car.

We surfed San Diego's beach boulevards in convertible mode, with the stereo cranked high and a California sun baking our skin. The only thing missing from our drop-top ride was a wind-battered hairdo. Those wizard-engineers at Lexus have managed to just about eliminate wind buffeting. Even at high speed, you feel little wind and can conduct a conversation with a seatmate without raising your voice.

Then we sealed the top for an eastward run through pine-covered mountains to speed and agility experiments in the low Anza Borrego desert. Pressed hard and fast through the wiggly routes, and then flat-out on the desert floor, the SC 430 revealed the aggressive side of its character, in spite of the luxury of its accommodations and the elite quite of its cabin.

Certainly, the SC 430 has all the right classic sports-car ingredients on board: a rigid platform with a stretched wheelbase, brief body overhangs front and rear, good weight distribution, and a front-mounted engine applying copious torque to the rear wheels.

That big engine, an aluminum quad-cam V8 measuring 4.3 liters, musters 300 horsepower at 5600 rpm and 325 pounds-feet of torque at 3400 rpm. That's sufficient motivation to hurl the SC 430 from 0 to 60 mph in 5.9 seconds, and to send it past the quarter-mile post in 14.4 seconds. Top speed, guaranteed to peg the radar needle of any law enforcement official, is 156 mph.

All that muscle channels through the five-speed automatic transmission that shifts discreetly, with Lexus efficiency. It has three programmable shift modes (normal, sport and winter) and a gated shifter mounted on the floor console. Thanks to the C-shaped gate, the driver can accurately flick the stick through all five gears for selective control that approximates a manual. Or leave it alone to make its own intuitive shift decisions.

SC 430 carries a complete complement of electronic controls to keep the wheels safely on course. The anti-lock brakes link to traction and yaw control systems that check tire slippage both forward and laterally.

Alloy wheels of 18-inch diameter are the largest ever from Lexus, and they carry low-profile Bridgestone or Dunlop performance tires monitored by a tire pressure warning system. Optional run-flat tires eliminate the need for carrying a spare tire in the tiny trunk. Opting for them increases luggage capacity from a measly 8.8 cubic feet to a meager 9.4. Puncture a run-flat tire and you can continue driving (for up to 100 miles) until you reach a repair facility. Run-flats can improve safety by eliminating the need to stop in a dangerous or unfriendly area. Run-flat tires introduce a ride quality that's rougher and not as quiet as the Lexus standard, however.