i advise you (when you are buying a used car) that you take with you one mechanic and if he say that the car is Ok, also you can take the car to the GERMAN for Car Inspection its in Salwa Road, this is the best place to check the cars, and they will give you a report then you can decide to buy the car o no, and in case you will decide to buy it, you can negotiate the price with the owner. Good Luck and Welcome to Qatar.