Toyota Supra Engine Rebuild?

This question is for a friend of mine regarding the cost of rebuilding a twin turbo supra engine. He is looking to a buy a Supra, and noticed that most have over 120k miles (understandable considering their age). He seems to have found one that runs fine, and is in good condition (both interior and exterior), however it has about 200k miles on it. What would it cost to buy this car and then pay for someone to rebuild the engine? Also, what other work would need to be done to the car to ensure it will run well into the future?