This 1973 Porsche 911 Carrera RS 2.7 Lightweight might be considered by some as the zenith of all classic Porsche 911s. The RS--built to meet homologation requirements--came with larger brakes, fender flares, a 210-horsepower engine and, of course, the now-iconic ducktail spoiler. Instead of using emblems, Porsche ran vinyl lettering down the side and thus the famous Carrera graphic was born--all in the name of saving weight. Porsche made 200 Lightweight …