expat boy

use
http://www.qatarliving.com/classifieds/cars

Here you can find good cars, you can negotiate the price and you can make a comparison between prices.
All this from your room(or... :)... office ).
Look for expatriates which are leaving soon .
Dont trust in the bullsI-I!t with "lady driven"!
Go with the car to a garage (should be your choise) and NEVER check the car in the night time.