The new GT3's naturally aspirated 4.0-liter flat six is derived from the latest engine used in the GT3 R and 911 RSR race cars.

Porsche has unveiled a new 911 GT3 this week in Geneva.

The latest GT3 is visually distinguished by a few exterior styling adjustments, but its highlight feature -- a new 4.0-liter flat six -- is tucked away in front of the lightweight carbon-fiber rear wing. Derived from the engine used in Porsche's thoroughbred 911 racers, including the GT3 R and 911 RSR, the new powerplant produces 500 horsepower and 339 pound-feet of torque without help from forced induction.

Weighing in at just 3,153 pounds, the car has a power-to-weight ratio of 6.4 pounds per horsepower. Drivers can expect to launch to 60 mph in 3.2 seconds if they opt for the standard seven-speed dual-clutch PDK gearbox. A six-speed manual carries a launch penalty of 0.6 seconds, though it achieves a slightly higher top speed of 198 mph instead of 197 mph.

Porsche refined the GT3's chassis with active rear-axle steering, pivoting the rear wheels either opposite or together with the front wheels depending on speed. Dynamic engine mounts and a locking rear differential also come standard.

Buyers are presented with a few more customization options inside. Standard seating balances sportiness and comfort. For those who prefer a plush experience, an 18-way adjustable seat is available, while the hardcore track junkies can opt for full bucket seats with fixed carbon fiber backrests.

The GT3 is scheduled to arrive in US showrooms this fall with prices starting at $144,650 (including freight).