my wife and i bought ourselves a second hand car from it's former owner through this site. this is steps we had done so far.
day one - negotiated and test drive
day two - paid for the car and have a middle man to do the transfer (paid processing fee which is not much)
day three - my wife received the transferred istimara (the car's istimara is valid until nov. 2012)
day four - my wife went to the insurance company, insurance recommended that the insurance can be transferred to her name before the istimara expires. and will be still valid until that day.

requirements: QID of buyer and seller, Driver's License of buyer and seller, Istimara of the car from the seller, transfer documents (from police station or middle men)