correct,
it all depends what you need to have done to your firearm.
while no customs detects some replacement springs etc in a friend's luggage,
in gerneral the Import of any spare parts for firearms is prohibited since august 2006, so for many parts you will not be able to get them sent from the much cheaper USA, you need somebody here who fabricates them.
and for many parts you would import for a much cheaper price you still would need somebody here to mount/change the pieces, if you did not buy them at his Shop his "mano de Obra" will not be cheap neither.
what kinda maintenance you need to get done?
Mike