I have the same question regarding a 2007 Sprinter 274RLS.
What I can tell you is that there is a video of someone repairing a bumper that was overloaded and failed due to metal fatigue:
https://youtu.be/YIwtglKiBwk. This alarmed me enough that I am considering a tongue mount instead:
Curt Clamp-on:
https://youtu.be/pD7dWdH4R5M
Arvika:
https://youtu.be/HHudvwfpAN0
Jack-it:
https://youtu.be/f1xheWrvN8o
Another alternative is the Swagman Over The Spare tire mount but after seeing the bumper repair video I think I would want to add the Mount n Go bumper re-inforcements.
Swagman:
https://youtu.be/UxH8reXYH9E
Mount n Go:
https://youtu.be/W7Ys33KTxHg
I haven't made a decision and would welcome feedback from the community.
Kelvin
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