Neanderthal sums it up nicely. Also two big things. DON'T use the cruise except to relieve fatigue. Except on lazer flat roads, it wastes fuel.. Also, are you really prepared to save a few dollars by driving 50 MPH? If so, you need to reevaluate what your time was worth. If you were an executive in my employ and you drove the company Mercedes 50 mph to save a few bucks I would replace you. If you save two gallons an hour at $3.00 per gallon then you must consider your time to be worth $6.00 an hour. Can you buy a MB on that wage today?