To estimate the price of the 2013 Audi A4 1.8L I4 30 TFSI (Base) with 173500 km mileage, I considered several data points. First, I looked at the selling prices of similar cars: a 2015 Audi A4 2.0 I4 45 TFSI Quattro (Top) with 119300 km sold for AED 41000 on 2024-02-07, and a 2015 Audi A4 2.0L Turbo I4 30 TFSI (Base) with 45300 km sold for AED 36000 on 2024-06-26. Given the target car is older and has higher mileage, its value should be lower. Next, I considered an offer accepted for a 2013 Audi A4 S-line 3.0T V6 Quattro with 190000 km at AED 22500 on 2024-01-08. This car has a more powerful engine and higher trim, suggesting the target car's value should be slightly lower. Lastly, I reviewed listed prices: a 2013 Audi A4 1.8L I4 30 TFSI (Base) with 173500 km listed for AED 25000, and a 2013 Audi A4 2.0L I4 45 TFSI Quattro (Top) with 149900 km listed for AED 22000. Considering these factors, I adjusted for the target car's average condition and higher mileage.