Guys, thank you for your reactions.

The car is a Euro indeed, because i live in Europe. But it doesn't match. The VIN number is one from a 280SE from 1982, but everything is post-facelift (>1985). That's why i have the M103 engine.
PawoSD I did not know that there was a difference between OM and M engines, that probably explains why i could not find that much information when i searched on google on OM103, lol

Ivanerrol, thanks. I will try to locate the number there tonight when i am home. Hope to find it there. But i know where to look know. That picture i used is one i found on the internet, mine is not that clean, but looks fairly nice though.