I started by looking at the selling prices of similar cars. The closest match is the 2014 Audi A6 2.8L V6 40 TFSI (Top) with 140850 km sold for AED 33900 on 2023-09-14. Another similar car, a 2014 Audi A6 40 TFSI (Top) with 95000 km, sold for AED 32000 on 2023-08-30. These cars have similar engine sizes and conditions but slightly different variants. The 2015 Audi A6 Quattro 2.8L V6 TC with higher mileage (185100 km) sold for AED 35000 on 2023-10-15, indicating a higher price for Quattro variants. The accepted offer for a 2014 Audi A6 40 TFSI (Top) with 95000 km was AED 33000 on 2023-09-17. Considering the target car's mileage of 138000 km and average condition, I estimate its price slightly lower than the 33900 AED sale due to higher mileage and being a mid variant, not top. The listed price of a 2014 Audi A6 Turbo I4 2.0L TFSI (Mid) with 163000 km is AED 25500, but listed prices are usually higher than selling prices. Therefore, I estimate the market price around AED 32000.