Robert,
Good luck with your future purchase.
One word of caution: Mercedes vehicles have been known to be addictive. By trying to set a limit of 3000 miles/year you may be setting unrealistic goals for yourself. Once you get behind the wheel of the V12 6.0 liter beast you will look for excuses to take the car out and find yourself taking the longest route possible.
But then again that is why we buy Mercedes.