Station wagon, say, in race, overturned (6,3)
I believe the answer is:
estate car
'station wagon' is the definition.
(estate car is a kind of station wagon)
'say in race overturned' is the wordplay.
'say' becomes 'state' (synonyms).
'in' is an insertion indicator.
'overturned' says the letters should be written in reverse.
'race' written backwards gives 'ecar'.
'state' placed into 'ecar' is 'ESTATE-CAR'.
(Other definitions for estate car that I've seen before include "Capacious vehicle" , "Motor vehicle" , "Vehicle with large area for goods" , "employed at Sandringham?" , "Brake" .)