Dear Sir,

No need to pay 20 % down payment to transfere your exesting car loan because you already paied it when you have the loan.
however, QNB offered a car loan promotion without any down payment and its easy to transfere your liabilities at any bank to QNB
i reccomend to transfere your loan to the above mentioned bank not because of the easy proccedure only but the prices and services are very compatitive too.