One of the shots struck the car's front seat passenger, who was blinded in his right eye as a result.
The incident happened in a cul-de-sac in the Rockmount area in the early hours of 28 January 2007.
The Police Ombudsman's Office was informed about the incident by police and launched an immediate investigation.
The scene was forensically examined and accounts obtained from witnesses, including police, the occupants of the stolen car, and local householders.
Investigators established that two officers had been on mobile patrol in the Comber Road area of Dundonald shortly after 1.30am when they noticed a Vauxhall Monaro car reported as having been stolen in Comber earlier that evening. It was being closely followed by a Volkswagen Golf.
The officers turned their car and followed the vehicles, which turned into Rockmount. The officers used their car to try to block the Monaro's exit from the cul-de-sac.
Having initially stopped at the end of the street, about five metres away, facing the police car, the Monaro then accelerated and struck the front of the police car before reversing.
The officers got out of their car and moved towards its passenger side where they believed they would be safer, given that there was more space for the Monaro to pass on the other side.
An officer then drew his personal protection handgun and shouted "armed police" but the car drove at speed, with tyres screeching, towards him. At this stage, he was between the car, the footpath and a garden wall.
The officer said he feared for his life and was aware that his colleague had been moving to join him and was also likely to be at risk.
He stepped onto the footpath to his left but by this stage he said the car was "on top" of him.
Fearing that he and his colleague would be killed, the officer said he discharged two shots in quick succession at the driver of the car.
One of the shots struck the passenger in the head.
The car then mounted the footpath and drove through the gap between the police car and the wall, narrowly missing the officer, before turning onto the Comber Road and stopping a short distance away.
The occupant or occupants of the Volkswagen made off on foot and have never been identified.
The officers provided first aid for the injured man, before their colleagues drove him to hospital, having decided not to wait for an ambulance.
A subsequent forensic examination of the scene established that one of the shots had lodged in the pillar between the driver's door and the windscreen of the Monaro.
The shot which struck the front seat passenger passed through his right forearm, struck him on the right side of his head, before finally lodging in the front passenger seat door. The bullet damaged an optic nerve, blinding the man in his right eye.
The driver was uninjured.
The Police Ombudsman did not identify issues or make recommendations as a result of this investigation, however, it is of course regrettable that a man suffered a serious injury as a result of this incident.
PSNI ACC Will Kerr
Forensic experts were commissioned by the Police Ombudsman's Office to reconstruct the sequence of events.
Although they were unable to conclusively determine the officer's position when the shots were fired, they estimated he had been between 2.4 and 4.9 metres from the car.
The evidence suggested that the bullet which struck the passenger had been fired through the driver's door window.
Statements were obtained from the two men who had been in the stolen car, who both accepted that they had been drinking alcohol on the night of the incident.
The passenger recalled that after the car had been driven forward he had felt a pain on the left side of his head and realised he had been shot.
The driver, however, said the car had been stationary and claimed it was only when the shots had been fired, shattering the window to his right, that he had then driven through the gap between the police car and the wall.
A resident said the shots were fired as the car appeared to be about to hit an officer, while another heard car engines, followed by the sound of a collision and two shots being fired.
A file of evidence was prepared on the incident and submitted to the Public Prosecution Service which directed that the officer should not be prosecuted for his part in the incident.
The Police Ombudsman, Dr Michael Maguire, noted that forensic evidence suggested the first shot was fired when the car was only a few metres from the officer, and the second when it was even closer. He said the officer would have had little or no time to react between the two shots.
He added that while officers were discouraged from firing shots at moving vehicles, legislation and guidelines did provide for rare occasions on which there was an imminent and seemingly inescapable risk of death or serious injury.
Dr Maguire concluded that the use of live fire had been justified in the circumstances, and made no recommendation for disciplinary action against the officers involved.
Assistant Chief Constable Will Kerr said the PSNI welcomed the Ombudsman's findings.
"The report stated that witness and forensic evidence supported the officer's belief that he and his colleague standing nearby were at risk of death or serious injury when he fired shots at the stolen car which was deliberately driven at him," he said.
"The legal and procedural framework in which police operate discourages the discharge of firearms at moving vehicles for a variety of reasons but also provides for those rare occasions on which police officers find themselves, or others, at imminent and seemingly inescapable risk of death or serious injury from the actions of those driving such vehicles."