This 1988 BMW M6 in Royal Blue Metallic is a fourth-owner car with 90k miles, owned by the current seller since 2003. It features extensive performance upgrades including a built S38B35 engine with a race cam, Euro headers, Dinan chip, upgraded brakes, and performance suspension, while maintaining a stock exterior appearance. The car is described as turn-key with working A/C, and includes all original parts for reversibility.