Used Cars: buying a car subect to lien, toyota financial, title document

Question
I plan to buy a car that has an outstanding car loan from Toyota Financial. I will have to pay off the loan as the seller is not in a financial position to do so. How can I ensure
1. As most of the cars are financed, is it a normal practice to buy / sell car with lien on it. If so what are the formalities I have to comply with.
2. If I pay off the car loan, will toyota financial send the title document to me?
3. What can I do to protect myself till the time the lien is drooped. I will be in the possession of the car.
4. What are the risks involved in such a transaction. I am not asking for an exhaustive list...anything will help.  

Answer
My advise to you is this.  If you can not get a loan elsewhere, in your name, I would stay away.  Get a loan from a bank or financial institution to pay Toyota off, outside of that, there really is not much you can do to protect yourself.  The title and paperwork is already done in whoevers name, and there really is no safe way to take over on the car, outside of putting the loan and title in your name.  If you are unable to do this, dont get involved, is my advise.