<prompt> Human: I just sold my old car for 4K. Im interested in buying my brothers Infiniti 2012 G37 coupe with 70k miles on it. He currently owes 11,500 on the car. KBB has that amount at trade in value. Retail is between 15-17kSuppose I gave my brother 3k cash, and refinanced the remainder of that loan into my name. Would this be a bad deal? It would be like buying from a dealership except I know all the cars history and know thats its been well kept and taken care of. My brother wants to upgrade to a newer car anyway, so we all win. Is there anything wrong with my logic here?  <response>: Just an FYI My G37S coupe averaged 14.3 mpg lol. Keep that in mind. 