Does the 2002MY M112 V-6 have an oil level dipstick? For some reason I don't think so. I'm not sure how I'd go about refilling the oil without a manual dipstick, but the new FSS computer must give some method.
I talked to an MB engineer that mentioned that the next generation of MB engines might not have drain plugs, as the suction method was so popular now.
You don't have to use a topsider on your car, as it still has a drain plug. I like my LiquiVac, as I don't have to drop the encapsulation pan or get under the car for a routine lubrication service.
The first time I used it, I dropped the pan and plug, to see how much would come out. Barely a few drops.
Either way is acceptable, but as Larry Bible says, "Change it hot, change it often."
1998 C230 "Black Betty"