The 2007 Porsche 911 Turbo is the first 911 to feature aluminum doors. Weighing just 24 lbs. total, they take 31 lbs. off the car’s total weight. In fact, the entire car, despite the addition of an all-wheel drive system, is 12 lbs. lighter than the previous model. At 3,495 lbs, its power-to-weight ratio is an impressive 1.4:1 or 1.4 hp per pound – very close to the Ferrari F430 at 1.5:1 and the Ferrari 599 GTB at 1.6:1. That’s some pretty good company. Of course, quality cannot be expressed in power-to-weight ratios alone. After all, the Dodge Viper boasts a 1.5:1 ratio, but it’s nowhere near as sophisticated as the Ferraris and the Porsche.