Stan buys a 1989 Ford Capri with the intention of repairing, restoring and selling it. He anticipates that it will cost him $20 000 to purchase, repair and restore the car, and that he can sell the finished car for $26 000. When he has spent a total of $10 000 on the project, he discovers that he needs to replace the engine. It will cost Stan $8000 to replace the engine. If he replaces the engine he can sell the car for $26 000. He can sell the car without the new engine for $18000. What should he do?