SPEED RACER.(Porsche 911)(Brief article)

Byline: ROSEMARY FEITELBERG

Drivers inclined to push the speed limit can now choose a more powerful Porsche, which may put state troopers on high alert. With 480 horsepower-60 more than its predecessor-the 2007 Porsche 911 Turbo covers zero to 60 mph in a mere 3.4 seconds. The sleek sports car, with a twin-turbocharged, 3.6-liter boxer engine and a $122,900 price tag, hits dealerships June 24.

The 911 has Porsche's first application of variable turbine geometry, a mathematical-sounding feature that allows for adjustable guide blades, said to improve flexibility and acceleration. There's also a redesigned all-wheel drive with an …