Whether you have an Aluminess roof rack or just a plastic storage box, the Sprinter roofs are a great place to store bulky things. The problem is how you get up there to strap everything down. Aluminess solves this problem with their all-aluminum ladder. These mount to the side of the vehicle, solving the problem of drilling through your rear door.
PLEASE NOTE: Sprinter High Roof and Low Roof require factory or after-market roof tracks for installation.