To estimate the price of the 2016 Mercedes GLS500 V8 4.7L Twin Turbo Standard with 156000 km mileage, I considered the listed prices of similar cars. The 2018 models with higher mileage (181000 km and 183000 km) are listed for SAR 174000 and SAR 160000 respectively. A 2016 model with lower mileage (95000 km) is listed for SAR 155000. Given the higher mileage of the car in question compared to the 2016 model listed for SAR 155000, I adjusted the price downwards. The 2018 models, despite being newer, have higher mileage and are listed higher, indicating a depreciation adjustment for the older model with lower mileage. Considering these factors, I estimated the market price accordingly.