Here Today, Gone Tomorrow: $10000 Sports Cars That Won't Be Cheap Forever - Yahoo Autos (blog)

1975-78 Datsun 280Z: The 280Z’s predecessor, the 240Z, has already taken its long-anticipated increase in price. The dirty little secret is that the 280 is actually the better car. The 280Z was essentially the original Nissan S30 sports car with modern Bosch L-Jetronic fuel injection. The last nice under-$10,000 280Z will probably sell somewhere in the U. S. in 2015. 3. 1987-1992 BMW E30 convertible: The E30 version of the M3 is already a valuable collectible and the sedan and coupe versions are popular with tuners. Source: