Some coupes (including mine
) suffered from water ingress through the rear quarter pinifarina badges which rots the inner sills - really you cannot inspect this unless you remove the rear quarter panel trim (which isn't difficult)
Pay particular attention to the outer sills - especially if it has side skirts fitted + usual areas prone to paint damage - rear arches etc
If not sorted properly & cut out, once taken hold inner & outer sill rust will spread to the body
Still alot of clean ones out there