I don't know what genius put the OM617 drain plug on the back side of the oil pan. The M103 drain plug is on the side of the oil pan, is easily accessible without lifting the car, and does as good a job of letting oil flow out of the engine as far as I can tell.

There are lots of opinions on oil extractors to help you decide for yourself. The only thing that is certain is that you DON'T NEED one. I have lots of things I don't need so a Topsider isn't out of place in my garage. I use it to extract engine oil, transmission fluid and power steering fluid. You can't completely drain a transmission or power steering system, but you can replace half the fluid with each oil change if you're inclined to do so.

We have an AT car that doesn't have a transmission drain plug. I extract what I can through the dipstick tube so I don't have to worry that the pan will come completely off before I'm ready for it to do so.

When I pulled the head off one of my cars I did an experiment of seeing how long it took oil to drain from the cylinder. Cold oil doesn't drain very quickly through the gaps in the piston rings so I used the extractor to clean up the cylinders. I also used the extractor to clean the head bolt holes in the block. I could go on but I'm sure you get the picture... that it's a useful tool, not that I'm an idiot

Sixto
95 S420
91 300SE
87 300SDL
83 300SD