1998 - 2005 Porsche 911s

Following more than three decades of proven success, the 911's air-cooled flat-six became water-cooled in 1998. Initially available as a 3.6-liter, 296-hp coupe or cabriolet, the 996 spawned nearly a dozen variants in a wide range of super-performance tunes.

Even before its release, debate ensued among 911 purists as to whether the "clean sheet" 996 could be said to qualify as a "true" 911. But the model would lay the groundwork for the next-generation 997, the highest-selling 911 in history.