people will tell you to go to the many shops on salwa road and industrial area..but there is actually only one truly competent and reliable option in qatar..the Bosch Service Center..its an international brand..they have outlets in Industrial Area and Wakra..contact number 44602142..Qr 500 for a bumper to bumper check that will tell you the exact condition of the car..best of luck..be very careful; a used BMW can be both heaven and hell