1. please provide a complete explanation, thank you

(b) OZX has spent $80,000 restoring his car and he plans to sell it at $180,000. However, in order for the car to worth $180,000, he needs to spend another $20,000 to replace the engine. Without replacing the engine, he could sell the car at $150,000. Should he replace the engine before selling? Why, or why not. Explain your answer with reference to (a) relevant principle(s) of economics. Nole: explain your answer by examining the marginal benet and marginal cost of replacing the engine before selling (compared to selling the car as it is now). [8 marks]