Mercedes-benz 300 SL Gullwing

K500’s Simon Kidston says, ‘Unquestionably the barometer of the market. Mercedes-benz’s peerless coupé tracks global trends like few others, so it’s no surprise that values have softened from the peaks of 2014 when an Ivory example hit $2.5m in Monterey. The 29 alloy cars are supervaluable but seldom appear for sale. Steel cars are judged by their spec (Rudge wheels command a 10% premium if factory-fitted), original colours (unusual is good, red is bad, silver is safe), and condition, given that a total restoration can cost $500k. There’s no more widely eligible or liquid classic.’