Under the hood of the 2007 Audi S8 is a 5.2-liter, 40-valve V10 engine cranking out 450 horsepower at 7,000 rpm and 397 lb.-ft. of torque at 3,500 rpm. This 4,277-lb. sport sedan hits 60 mph in only five and is electronically limited to a top speed of 155 mph. A six-speed Tiptronic automatic transmission with a Sport mode and shift paddles on the steering wheel is standard. Surprise! The 2007 Audi S8 has a tow rating of 5,000 pounds.