In an automotive world in which long legacies of high-performance are continually trotted out and watered down for commercial appeal over time, it can be hard to find examples of restraint. That word might not be the most apt descriptor of Porsche 911 models that wear the italicized “RS” on their rumps, but the company has shown plenty of it over the last half-century by resisting the urge to turn their legendary Rennsport treatment into the equivalent of a glorified sport package for soccer mom Macans. Since the very beginning, Porsche RS road cars have meant nothing but business.