The venerable 911, in many ways unchanged for nearly 40 years, but in others almost completely different to the original, is in the process of a mid-cycle update, and with the 911 Carrera and Carrera S already refreshed , the latest models to get the new mechanical upgrades include the all-wheel drive Carrera 4 and Carrera 4S variants. Very few appearance modifications have been made, with engineers instead focusing on improving performance while also reducing fuel consumption.

Both the coupe and cabrio variants of the cars are included in the updates, as will the 911 Turbo and its cabrio cousin when both are finally unveiled later this year. Highlighting the 2009 model year facelift is the introduction of a seven-speed Porsche Doppel Kupplung (PDK) dual-clutch gearbox and... // CarCental

STUTTGART, Germany — A few weeks after the debut of the 2009 Porsche 911 Carrera , the German automaker has unwrapped its all-wheel-drive companions, 911 Carrera 4 and Carrera 4S, in both coupe and convertible variants.

The Carrera 4/4S, which arrive at U.S. dealers in late October, get many of the same styling tweaks as their rear-wheel-drive siblings, including new bi-xenon headlamps and LED taillamps.

Unique to the Carrera 4/4S is a new electronically controlled all-wheel-drive system that bundles Porsche Traction Management (PTM) with a mechanical rear differential.

Porsche's new direct-injection flat-6 engines and the... // Edmunds.com/Inside Line

Jalopnik (Enlarge photo)

Though we've yet to get our Cheeto-stained hands on the 2009 Porsche 911 , the testers at Popular Mechanics had the chance to roam the Stuttgart roads in a few variations, finding the new model to be Porsche par excellence . They also found the new Porsche's wizardly dual-clutch PDK gearbox to be a vast improvement over the previous Tiptronic transmission. And those famous Porsche flat sixes? Both the Carrera and Carrera S get power increases to... // Jalopnik

Automobile Magazine (Enlarge photo)

In typical Porsche fashion, the updated 911s are being rolled out in batches. We've already driven the coupe and convertible versions of the Carrera and Carrera S; now there are four more models, all with four driven wheels.

The big news for the Carrera 4 and Carrera 4S coupes and convertibles is a new-to-Carrera all-wheel-drive system that's been nicked from the 911 Turbo, called Porsche Traction Management. The electronically controlled system replaces a viscous multi-plate clutch.

Engines and transmission choices mirror those found on the non-4 Carreras. Both engines now feature direct injection, which adds power while increasing fuel economy. The Carrera 4 gets a new 3.6-liter flat-six producing 345 hp and 287 lb-ft of torque, while the 4S features a 3.8-liter that sends 385 hp and... // Automobile Magazine

Like their rear-wheel drive brethren, both the 2009 Carrera 4 and 4S receive a bump in output to 345 and 385 horsepower, respectively. This represents an improvement of 20 horsepower for the Carrera 4's 3.6-liter flat six and a full 30-horse jump for the 3.8-liter in the 4S. Both cars also get the same PDK (for Porsche-Doppelkupplung) seven-speed, dual-clutch gearbox, which replaces Porsche's venerable Tiptronic S and actually makes the cars 0.2 seconds faster than versions you shift yourself. A six-speed manual is still standard across the line, but impressively Porsche also claims PDK-equipped 911s achieve lower emissions and better fuel-economy.

Visually, the all-wheel drive 911s retain their 1.73-inch wider stance compared to the regular Carrera, and the 4 and 4S are now set apart by... // MotorTrend Magazine

MotorTrend Magazine (Enlarge photo)

Consider the 2009 911 a brand-new car, even though the basic structure remains essentially the same as the outgoing model's. Two entirely new and more powerful engines and a new twin-clutch automatic transmission are the major refinements to Porsche 's 45-year-old model, but there's much more to the transformation than the powertrains.

Suspension, brakes, lighting, interior and exterior styling all were massaged for the Carrera and Carrera S,... // MotorTrend Magazine