1958 Porsche 550A Spyder Above 29 June 2018 The 1958 Porsche 550A Spyder, chassis 0141, estimate $4,500,000 to $5,000,000, is the most-expensive car on offer at the Mecum Monterey 2018 collector car auction. NOT SOLD. Highest bid $2 million © Courtesy of Mecum