2003 Infiniti FX45 750 I

The new Infiniti FX45 is quicker than Porsche's new Cayenne S. Specifically, the FX45 can zip from 0 to 60 mph in slightly more than 6 seconds, while the Porsche Cayenne S takes a bit longer. How can that be? Though the Porsche is more powerful, the Infiniti has a better power to weight ratio. The 315-horsepower Infiniti FX45 weighs about 600 pounds less than the 340-horsepower Porsche Cayenne S. Do the math. (Actually, we'll do it for you: The 4,949-lb. Porsche uses 1 hp per 14.5 lbs.; the 4300-lb. Infiniti has 1 hp per 13.6 lbs.) Infiniti claims the FX45 is quicker than the other hot-rod SUVs, namely the Mercedes M55 AMG and the BMW X5 4.6is. At the same time, the Infiniti models cost less than their German counterparts. These performance and pricing advantages come partly by making a conscious decision that Infiniti's new luxury sport-utilities would not be designed to go off-roading. Therefore, the FX45 frame could be lighter, lightening the load for the Infiniti V8.