When it hits the streets the streets later this year, the Mercedes-Benz CLK63 AMG will be packing 481 horsepower under the hood, representing a 31-percent gain over the model it replaces. As befitting an AMG model, this ride also includes high-composite front brakes, a sport-tuned suspension, a Speedshift 7g-tronic automatic transmission, and unique 18-inch alloy wheels rolling on 225/40 tires up front and 255/35s out back.