Preheat oven to 350°. Grease and flour tube or bundt pan. Grate the bar of German sweet chocolate and reserve 1/4 cup for the topping. Combine cake mix, pudding, eggs, water and oil. Beat with mixer 5 minutes on medium speed. Add chocolate chips and grated chocolate to batter. Fold together. Pour batter in pan and bake 45 to 50 minutes, until cake pulls from pan or toothpick comes out clean. Let cake cool 15 minutes in pan, then loosen edges and turn upside down onto plate. Chocolate chips on the bottom of the pan may stick, so leave pan inverted on serving plate. While cake is still warm, combine powdered sugar and the 1/4 cup of grated chocolate in a sifter and sift it over top of cake. Enjoy!