Is the Porsche Cayman GT4 a good investment?

The thesis

The 981 GT4 (385hp, 3.8L flat-six, manual-only) was the first mid-engine Porsche GT car and the last NA Cayman before the 718's turbo-four. It sits as a cult favorite among purists. However, current values (~£64k–£96k) fall well below the user's £80k floor, and the 718 GT4 (982) and recent GT4 RS have diluted exclusivity. The 981 has already peaked and stabilized; it's not positioned for another leg up.