I’m thinking of buying a 91-93 840Ci or 850Ci. How much should I expect to pay for each. I heard that the 4.0L engine has some problems. Can you tell me if they’re big problems. Also is there a stick shift of 840Ci or is it only the 850Ci. Which one is a better buy? How much is the insurance cost for 840Ci and 850Ci?