This may sound stupid :, but I have been wondering about a HOT air intake in a diesel that maybe hovers over the exhaust manifold, and plumbs up to the air cleaner. Why? You ask? Obviously, in the summer, MPG is better than winter. My highest MPG is 63.43mpg, and that was in July 2012 where the temperature that week averaged around 100 degrees with high humidity. I know diesels run more efficiently when warm. I understand I would probably reduce my performance, but I'm not driving a Rabbit to drive fast. Does anyone think that I could increase my mpg by doing this ?