Preheat oven to 350 degrees. Prepare cake mix according to package directions, substituting margarine for oil. Reserve 1 cup of batter. Pour remaining batter into a 12 cup greased and floured fluted tube pan. Combine cream cheese and sugar, mixing well at medium speed on an electric mixer until well blended. Blend in eggs, one at a time. Pour over batter in the pan. Spoon reserved batter over cream cheese mixture. Bake 1 hour or until toothpick inserted in center comes out clean. Cool 30 minutes; remove to a wire rack. Combine margarine, chocolate and corn syrup in a small saucepan. Cook over low heat until chocolate is melted. Pour over cooled cake.