To estimate the price of the 2015 Mercedes S400 V6 3.0L Standard with 86000 km mileage, I reviewed the listed prices of similar cars. The closest match is a car with the same specifications and mileage listed for SAR 165000. Other similar cars with slightly higher mileage (e.g., 86600 km) are listed for SAR 210000, and cars with significantly higher mileage (e.g., 101000 km) are listed for SAR 190000. Given that the car in question has average condition and the listed prices tend to be higher than actual selling prices, I adjusted the estimate downwards from the lowest listed price of SAR 165000 to account for negotiation and market conditions.