The Ferrari 250 "Ferris Buehler" replica doesn't look quite right, especially around the grille. Also, there were so few of the real ones made that anyone who knows cars will KNOW it's a phony. What kind of chassis and engine does it have? The Porsche makes sense, since a 356 wasn't much more than a heavily modified Beetle anyway. With the right spec engine and some suspension/brake mods, it could be "close enough" to the experience of a real Speedster. I'd keep it, unless it's a really cheesy replica.
The red '62 'Vette is expensive partly because that's the "Buzz & Todd" car from "Route 66".