How to buy a car (Ho Chi Minh City)

Hi -- I'm American and my wife is Vietnamese. We've decided to buy a car. I've never purchased one before in Asia. We want to buy new. We're considering taking a loan from a bank. What are the things to look out for? Pitfalls? Red flags? We'd also like some information as to which model/brand of car to buy. High on the list at the moment is the Protected content City.