PREHEAT oven to 350°F. Spray 10-cup tube pan or 12-cup fluted tube pan with cooking spray; set aside. Beat eggs, cake mix, 1 cup of the sour cream and the oil in large bowl with electric mixer on medium speed 2 min. Pour into prepared pan.
BAKE 40 min. or until wooden toothpick inserted near center comes out clean. Cool in pan on wire rack 10 min. Run knife or metal spatula around edge of pan to loosen cake. Invert cake onto rack; gently remove pan. Cool cake completely.
MIX remaining 3/4 cup sour cream, the coconut and sugar in large bowl until well blended. Gently stir in whipped topping. Spread onto cake. Store in refrigerator.