How tall is it? If it's the really long one, you've got about 14 feet between the back of the driver's seat and the rear doors. The side dimensions will be slightly narrower than the Ford or Chevy, figure about an inch narrower. In between the wheel tubs, you have maybe 50 inches, as compared to 52 inches for the Ford. In my old one, which had the super-high top, I guess six feet is about right-- measure yours to be sure.
About the height: I've seen one with a really high top, higher than the one I had. His had a translucent roof too. He had the 3500 so I have doubts his Sprinter would be much good in Expedited.
Problem: They make these things in half a dozen different sizes, so we almost need a picture of the machine to be able to tell you much.