I think an Al Quaeda strike is a real possebility here. It cannot be ignorred for reasons of labelling it "German islamists" instead og Al Quaeda.
The G8 would be a tempting target. Maybe not locally, but time-wise: it could be targetted although striking somewhere else - but at the time of the summit. That does not mean that I read too much into today's thread warnings. As I understand it, the source mainly is the American intel community, and you never know how much of what they say is true, and what is opportunistic manipulation. The Secret Service is paranoid anyway
I'm sure they made the BKA already boiling with anger at 98°C again
The police raids against several left and autonomous groups are still debated. when the police had indications for these groups planning violant acts, no matter if it conjunction with the G8 summit or not, they would have had an obligation to act.
The present revival of the debate about the RAF in the medias is a stupid hype only, caused by the Klar-affair, or better: the timetable of it: Klar's call for clemency just has deen rejected by the president. That's all there is about the RAF. It's as dead as it can be.
The immediate present's events are only an attempt to reduce the expected protests during the summit to meaninglessness. Hopefully there will be also no international news reports about huge crowds trying to chase the bosses into the sea - that is what they try to prevent... The demonstrations will be held, but they want them to be held far away where they are not heared, and will no be taken too much note of, and thus can be ignorred. "Silent!", is the motto.