The Porsche 911 lineup starts with the Carrera, powered by a 3.6-liter version of Porsche's classic flat six-cylinder engine generating 325 horsepower and 273 pound-feet of torque. The Carrera S and Carrera S Cabriolet are powered by a 3.8-liter six-cylinder, delivering 355 horsepower and 295 pound-feet of torque. The new Carrera 4 is equipped similarly to the standard rear-drive Carrera, but with the added advantage of all-wheel drive. The all-wheel-drive 911 Turbo S gets Porsche's race-bred, twin-turbocharged version of the 3.6-liter engine, creating a whopping 444 horsepower. Safety features on all models include Porsche Stability Management and curtain-style head protection airbags, which deploy from the doors and augment the front and side-impact torso airbags.For 2006, new Carrera 4 and Carrera 4S models join the Carrera and Carrera S models that were introduced for 2005. Cabriolet versions also join the 2006 Porsche 911 lineup.