If you're not much a classic car nut, and you were to walk up to a stylish little 1968 Opel GT, like this one, you'd probably think "Wow, is that... Italian? It must be fast (for its age)."
Of course, you would be wrong. The Opel GT is, in fact, based on the rather pedestrian Opel Kadett - seen here. The GT was not particularly quick, expensive, or really even that rare.