Cake: Beat eggs at high speed with electric mixer for 2 minutes. Add sour cream 1/3 cup water, and next 2 ingredients, beating well after each addition. Add cake mix, beating at low speed just until blended. Then beat at high speed for 2 minutes. Pour batter into a greased 13 x 9 inch baking dish.
Bake at 325 degrees for 40 to 45 minutes or until a wooden pick inserted in the center comes out clean. Cool the cake in the dish on a wire rack. Cover with plastic wrap, and freeze for 30 minutes. Remove cake from freezer and spread frosting on top of chilled cake. Cover and store in refrigerator.
Frosting: Beat cream cheese and butter at medium speed with an electric mixer until creamy; add milk and vanilla, beating well. Gradually add sugar, beating until smooth. Stir in coconut (makes 4 cups)