Thanks for the hint,
it could be the engine mount however the engine running rougher and idle-dip when warm-starting came all along with these annoying vibrations (car was doing great and very very smooth until then), so I really believe it is something with the fuel injection or a kind of misfire, ignition coils ....?
Any additional idea ??? Anybody there had same kind of problem? (..and solved it
Thanks again for your feedback !!