Now this one doesn’t involve supercars or driving but it probably takes the cake for most expensive. From WP:
During the early hours of 14 December 2002, while traveling from Zeebrugge to Southampton with a load of nearly 3,000 automobiles, she collided with the Kariba, a 1982 Bahamian-flagged container ship. The Kariba was able to continue on, but Tricolor sank where she was struck, some 20 miles north of the French coast in the English Channel. While no lives were lost, the ship remained lodged on her side in the mud of the 30 metres (98 ft) deep waterway.
The cargo of 2,871 new cars – mostly from premium German and Swedish manufacturers including BMW, Volvo and SAAB – was removed from the wreck and destroyed, approximately £30m (representing a retail value of £60m) worth. Most oil was removed from the ship’s tanks soon after it sank, but during the salvage there was a small 540-tonne oil spill, sparking concern.