The 4S is the higher-performing version of Porsche's glass-roof 911 Targa.

Like the Targa 4, it features intelligent all-wheel drive.

But unlike the Targa 4, it has a bigger engine in its 3.8-liter boxer six-cylinder with 355 horsepower (30 horsepower more) and 295 pound-feet of torque (21 pound-feet more).

This gives the 4S brisker acceleration from zero to 60 mph in just 4.7 seconds (0.4-second quicker) and a higher top speed of 179 mph (five mph faster).

The power is routed to all four 19-inch alloy wheels via a standard six-speed manual transmission or optional Tiptronic S five-speed automatic (with steering wheel rocker switches for self-shifting).

At least some power, a minimum of five percent, goes to the front wheels at all times with up to 40 percent being diverted in low-grip situations. Otherwise, the Targa 4S is predominantly rear-wheel drive and retains most of this layout's handling characteristics. Porsche says that in typical driving situations the split is 65/35 rear to front.

Along with Porsche Stability Management, the all-wheel-drive system also helps to shorten stopping distances.

The 4S also benefits from standard Porsche Active Suspension Management, an electronic control system with two settings (normal and sport) that uses continuous damper adjustment to maintain optimum ride quality and comfort.

The unique feature of a Porsche Targa model is, of course, its large power glass roof. It gives the vehicle a convertible feeling without the complexity of a folding roof and with better protection from weather elements. Even when it's closed, the roof offers up the sky to the 911's occupants, unlike a convertible.

Most features are standard on the Targa 4S (including many that are optional on the Targa 4) but some of the available options include the Porsche Ceramic Composite Brake system, Sport Chrono Package Plus, stainless-steel exhaust pipes, self-dimming rearview mirrors, parking-assist sensors, navigation system and high-end Bose audio system.