Admit it: you've done this at least once. Curiosity on Craigslist has led you to search for one of the internet's most loved -- some would say overhyped -- used cars, the E30 BMW 3 Series from the 1980s and early '90s. And then you found a truly beautiful one. And then you saw that one letter at the end of its numerical name that serves as an instant disqualifier: e.