Properties of cars (7)
I believe the answer is:
estates
This clue is a double definition.
'properties' is the first definition.
(I know this)
'cars' is the second definition.
(estate is a type of car)
'of' acts as a link.
(Other definitions for estates that I've seen before include "residential areas" , "Extensive landed properties" , "Property?" , "lands for development" , "Country properties" .)