Police said the red Porsche 911 GTS was travelling west along the A281 Guildford Road, in Rudgwick, before it crashed 200 metres east of Hillhouse Lane on Friday evening (August 24).
Emergency services rushed to the scene with the Air Ambulance helicopter landing in a nearby field at about 7.30pm.
A 30-year-old London woman, who was a passenger in the car, suffered serious injuries and was flown to King’s College Hospital in London.
Police said she remains in hospital and her injuries are not thought to be life-threatening.
The car driver, a 40-year-old man from London, suffered bruising and a suspected broken collar bone and was taken to the Royal Surrey County Hospital in Guildford. He has since been released, officers added.
Anyone with any information is asked to contact Sussex Police online or by phoning 101, quoting Operation Sedgefield.