When it comes to powering your 2006 Saab 9-5, the choice has already been made for you. Saab is only offering a 2.3-liter turbocharged four-cylinder that now produces 260 horsepower and 258 lb.-ft. of torque. One ingenious bit of technology is the engine management system that can produce up to 273 lb.-ft. of maximum torque with the standard manual transmission, but only under full throttle. If the manual transmission is not your cup of tea, there is also a five-speed automatic available with steering wheel mounted shift buttons.