If you have not signed the loan agreement, and have not parted with your down payment, then there is no problem if you wish to abort the deal. But you may need to discuss with the seller /outlet on any booking you have paid.

Once your loan agreement is signed, the dealer may proceed to register the car. If the car is not yet registered, then you still have a chance to abort the deal. However, if the car is already registered, then there is no backing out anymore.

Having said that and as a general statement, I hope and urge all those who wish to buy cars to think thoroughly before committing to a purchase.  It is not good to give the sales people the run around, only to change your mind at the last minute, after all the effort he/she has made to secure the loan for you.