Admirers of the Porsche 911 would insist that no other model in the auto industry has stayed so true to its original formula, a production life span that is closing in on 50 years. Yes, the Chevrolet Corvette celebrates its 60th anniversary this year, but the muscle-bound 2013 version is hardly cut from the same cloth as Harley Earl’s tepid roadster of 1953.

The 911, on the other hand, still carries the distinctive profile of the model that made its debut at the 1963 Frankfurt motor show. Its engine is still an opposed 6-cylinder, and it is still placed at the rear.

One thing that’s not the same is the model name: initially, the new Porsche was labeled the 901, but the road car was renamed the 911 because a French automaker, Peugeot, held the rights to three-digit model names with a zero in the middle.

At the time, Porsche’s visionary designers could hardly have imagined that their sports car would still be thriving and evolving a half-century later. Although the 911 has added weight and girth over the years, it has also been transformed, continuing as a benchmark for all-around performance.