You could drive Ford Mustang the 500kms outright without any stops but it is recommended that you let the engine rest every 130-150 km just as a precaution to avoid overheating or other mechanical problems.
Well, in order to purchase a car you need your documents which prove your identity and to apply for a loan you will need a pan card. However, the down payment remains in between 20-30% of the on-road price of the vehicle and ROI varies between 9.25-11.5% and it totally depends on the CIBIL/Credit score of an individual. So, we'd suggest you walk into the nearest dealership to know the final finance quotation and documentation as they will be the better person to assist you. You can click on the following link to see the details of the nearest dealership and selecting your city accordingly - Car Showrooms.