Even though you are a little far away, I could do the service on the ML. I would get the Warrentech warranty. The reason is the Starmark extended warranty locks you into the dealer.
With the Warrentech, you can go to any MB shop (MB Autowerks is the best
and have repairs done. Don't get the least expensive one, they don't cover anything. Also, shop around. Some dealers are less expensive on the extended warranty.
I read a service information that was sent to ML owners. It urged them to change to synthetic oil. If I had one, I would use synthetic and change it at 5k intervals.