Hi, I hold an american drivers licence and I am moving to Berlin. Before I move I am installing a motor kit into my bicycle. I have a few questions regarding laws to ride it in public roads. 1) Should I get a 50 cc or 80 cc? 2) Since I have a drivers licence already what else will I need to get to be able to ride it in public roads. 3) How easy/difficult is the written and practical test that you have to pass to ride them? Any additional info is so much appreciated guys. Thanks a lot! Seb.