To estimate the price of the 2018 BMW 730 i6 3.0L turbocharger Li (Top) with 120000 km mileage, I first looked at the selling prices of similar cars. The closest matches were: 1) A 2018 BMW 730 I4 2.0L Twin Power Turbo with 92000 km sold for 138000 SAR on 2024-02-27, and 2) A 2018 BMW 730 Li I4 2.0L Twin Power Turbo with 101000 km sold for 132000 SAR on 2024-08-12. Both cars are of the same variant (Li Top) but have smaller engines (2.0L vs. 3.0L). Given the larger engine size of the target car, it should be valued higher. Next, I reviewed listed prices: the highest was 148000 SAR for a car with 99000 km, and the lowest was 130500 SAR for a car with 150000 km. Considering the target car's mileage of 120000 km, it falls in between these ranges. Factoring in the larger engine size and average condition, I adjusted the price slightly higher than the average selling prices but lower than the highest listed price.