Back in the '50s, BMW wanted to storm the U.S. market with this sporty roadster that catered to the wealthy clientele. The selling price was so crazy-high that only 254 were sold, almost bringing BMW into bankruptcy. The good thing is this rarity makes the 507s ever so precious and almost impossible to find on the market. This is why this 1958 Series II example is a steal at $2,450,000.