> Even with a warrant the data collected by FRA wouldn't be legal to use in a court if both parties (sender and receiver of a message/whatever) was in Sweden (regardless of whether the traffic took a detour across the border or not (too/from gmails servers for instance)).

That does not make me fell much safer. In Sweden there is nothing preventing illegally obtained evidence to be used in court. The idea is that the one obtaining the evidence will also be punished for his crimes, but I can easily see that case not even reaching court.