I filed up the gastank with unleaded in stead of regular.
after 2,5 miles (fueltank wal allmost empty when i filed it up)the engine was competly dead.does anybody know's if that could be the problem?
And is it possible any engine damage is coused by this?

 

I take it your not in the u.s As for U.s versions / and german mb recommends 92 octane unleaded if you have a gas version. as for putting in lesser grade unleaded 87 or 89 youll get crappy performance and may experence knocking or sluggish performance depending on engine and calibration of me module. a Sl 55 will react way different then a c320 now if you ran out gas you may have caused some damage to fuel pump being that it use the fuel as a cooling source so the lower the tank level the less fuel the pump may runn hotter not getting proper cooling and if it old over 100k it ma be damaged.