To estimate the price of the 2012 Mercedes S300 V6 3.0L Twin Turbo with 166000 km mileage, I considered the listed prices of similar cars. The 2013 models with similar specs and varying mileages were listed for SAR 55000, SAR 89000, SAR 103000, and SAR 79000. The 2011 model with higher mileage was listed for SAR 52500. Given the 2012 model's average condition and mileage, I estimated its price to be slightly lower than the 2013 models but higher than the 2011 model. The average of the 2013 listings is around SAR 81500, and considering depreciation and condition, I adjusted the price downwards to reflect the 2012 model's market value accurately.