Porsche enthusiasts have almost always paid a lot more for a small delta in performance or for the sake of originality. Take the 964 C2 - basically an $18K car. An RSA is very, very similar, but goes for 2x that, around $36K. A very low production number and moderately better US Carrera Cup goes for north of $100K in good, untracked condition. As has been pointed out repeated, if you take the $18K and another $5-10K, you can build a pretty awesome 964. And some do. And some buy RSAs.
The midyear Carreras were the last cars where the "Carrera" was the top of the line (in looks, for the US
and in reality ROW). After that, the Carrera (starting in 1984) became the base model.