Sorry to dishearten you but it is really tough to open your own Automobile company in these types of packed competition from all the Automobile companies. Just don't think of owing a simple company, designing crazy cars, driving at full throttle and all. Think beyond these things, think from a market perspective.

First you will open your company then you will start making your own cars, you will have to acquire lots and lots of land, Labour, laws.

You will have to open the customer support, Maintenance unit, spare parts and all.

I am trying to discourage you but before taking any such decisions, go through the articles of DC avanti and Vazirani Shul.