mercedes actually put magnetic oil drain plugs from the factory on european models. if you need to find one for your car you can check for junked euro models!
eric

__________________
1995 E320 Sportline Wagon "Bernard"
black on black leather

http://i.imgur.com/BdZ7jM3.png

I don't think the MB oil filter design lends itself to using the magnetic collar. The filter is a cartridge type unlike other manufacturers that use a disposable canister. Anything debris caught by the magnetic collar would either have to drain all the way down from the top (like on my E320) or need to get washed out (an extra step) of the plastic cap.

__________________
95 E320 Cabriolet, 159K