Thieves may have stolen more than 100 car parts worth $500,000 from a Kowloon Bay shop for use in next month's Macau Grand Prix, police said yesterday. The items, including turbo components, computer units, brake parts and pistons, were designed for modifying vehicles and enhancing performance, a police investigator said. The robbery took place at about 6am when a tow truck was used to force open a metal shutter at the front of Improve Power Performance in Wang Kwun Road. The truck, later found nearby, had been stolen. The officer said the gang had deactivated an alarm system before the raid. Four masked robbers were seen removing cartons from the shop and loading them into a van. The gang made off in the van, also thought to have been stolen. Since the motor parts were designed to enhance performance, police did not rule out the possibility they had been stolen for use in the upcoming Macau races, he said.