This year the buzz at Porsche is the arrival of the first performance sedan in the company’s history. The Panamera sedan fills the gaping hole left in the product lineup after the arrival of the Cayenne. The Panamera now gives Porsche a complete line of performance vehicles.

The 911 line of sports coupes and cabriolets are still Porsche’s calling card. These are the cars that define the company and set the bar for other automotive manufacturers’ sports machines.

I recently had the opportunity to test the 911 Carrera 4S Cabriolet, which has undergone some refinements for 2009.

The “4” designation signifies all-wheel drive and the “S” means that the most powerful engine has been squeezed in.

The cabriolet boasts several important refinements over the 2008 versions. Chief among these refinements is under the tail, where Porsche added new, more potent and more fuelefficient engines. My test car had the top engine: a 3.8-liter, water-cooled, horizontally opposed six-cylinder. This engine is equipped with a direct-fuel-injection system that helps boost output to 385 horsepower and 310 feet-pounds of torque and provides better fuel economy. By comparison, the top motor last year had only 355 horsepower and 295 feet-pounds of torque.

I know most sports car aficionados out there cringe at the thought of driving any sports car, especially a Porsche, without a manual transmission. However, driving in Chicago traffic on a daily basis can take its toll. So, new for this year, Porsche offers an optional ($4,080) driver-shiftable Porsche Doppelkupplungsgetriebe (a k a PDK).

This advanced seven-speed double-clutch automatic transmission is lighter, more efficient and quicker shifting than the previous Tiptronic S.

The seven-speed automated manual gearbox uses two clutches to deliver super-fast shift times and improved fuel efficiency. You can shift the seven-speed PDK up and down automatically or shift via steering-wheel-mounted paddles or the console-mounted shift lever.

Fuel economy numbers in cars of this class are really irrelevant, but for the curious the cabriolet gets 18 mpg city and 27 mpg highway. I did not achieve those numbers – though I made sure I wore my heavy shoes that week. However, these numbers do help the Carrera 4S Cabriolet evade the dreaded “gas-guzzler” tax.

The conversion from top up/down took approximately 20 seconds at the touch of a button. The top may be deployed while the car is moving – something I appreciated when rain storms suddenly popped up. The standard wind deflector made for a quiet and buffeting-free passenger cabin, allowing for conversation or listening to the Bose audio system.

Taking this car out for a quick spin is a drive you’ll enjoy. While the ride is on the firm side, it won’t jar your fillings loose.

Find a curvy back road and you’ll be blessed with some outstanding performance.

The engine and transmission work hand in glove to deliver lightning-fast acceleration and response. The manual mode is not overly intrusive, allowing you to really wring this car out.

Another change this year is that the engine’s power is distributed to all four 19-inch wheels via the same electronically controlled Porsche traction management system found previously on the Porsche 911 Turbo. The PTM can vary the torque split infinitely between front and rear wheels as needed for optimum traction.

However, PTM directs two-thirds of the engine’s torque to the rear wheels under normal driving conditions.

Porsche engineers firmly believe that braking performance should be greater than acceleration performance. My test car came with 13-inch vented rotors and the monobloc four-piston calipers are now the same as those used on the 911 Turbo. Critical refinements have been made to the airflow around the wheels to increase all-around brake cooling. All braking was straight and true without any pedal vibration.

Acceleration is unreal: the car reaches 60 mph in approximately 4.5 seconds and Porsche claims a track-rated top speed of 185 mph. While it’s hard to justify that kind of power for the street, it is impressive.

Stepping on the gas produces a wonderful exhaust note.

Visually, car spotters will note the Carrera 4S Cabriolet is distinctive from its two-wheel-drive brothers by its brawny stance and muscular fenders. Upfront the most notable differences are the new, horizontal covers for the bi-xenon headlights and the LED daytime running lights, which extend over the air inlets. In the rear, all the lighting elements except for the reversing lamp are light-emitting diodes. Finally, the 911 Carrera 4S Cabriolet has dual, round, polished exhaust ports in the back.

As for comfort, taller drivers will probably wish for a bit more legroom. The beige leather seats were a tad firm, but supportive.

The 911 does come with rear seats, but it will hold groceries or small items. I had my seatback resting completely against the bottom of the rear seat so even young children would not fit.

Porsche increased driver and front passenger comfort and convenience this year with the availability of ventilated front seats and through the redesign of the Porsche communication module, which boasts a larger screen, simplified operation, Bluetooth connectivity and the ability to play music from external sources such as iPods and MP3 players.

As for luggage/storage, make sure you pack light because the front luggage compartment is small at only 4.4 cubic feet.

Cup holders are flimsy, so be careful with your hot beverages. My 911 Carrera 4S tester started at a cool $102,800, but that was just the start.

To that princely sum Porsche checked off the boxes for special Ruby Red Metallic paint, leather interior, power comfort seats, PDK transmission, self-dimming mirrors, heated front seat and steering wheel, seat ventilation, sport chrono package, Bose stereo, XM radio, floor mats, multifunction steering wheel-PDK and universal audio interface. So, with the destination charge, the grand total came to $120,100.

While new products drive consumer interest and excitement, over the years Porsche has been able to refine and inject new life into the 911 line. This car is a true all-weather machine that can put power to the pavement and uphold the Porsche driving reputation. It will put a big grin on your face.

2009 PORSCHE 911 CARERA 4S CABRIOLET

ENGINE: 385-horsepower 3.8-liter six-cylinder

TRANSMISSION: Doppelkupplungsgetriebe (seven-speed automatic)

DRIVETRAIN: all-wheel drive

FUEL ECONOMY: 18 city/27 highway

BASE PRICE: $102,800

AS TESTED: $120,100

WEB SITE: Porsche.com