I am looking to change my towcar to either an E Class Mercedes or a 5 series BMW. My dilemma is whether to go for the more popular automatic gearbox option. I have read somewhere before that towing with an auto can lead to overheating (not sure if it was referring to the engine or the gearbox). However, I am looking at a minimum of 2.5 litre for a BMW but more than likely a 3.0 or 3.2 litre engine. I will be towing our 2 berth Hymer Nova 470. Am I worrying about nothing or do I really need to find a car with a manual box?