Heat oven to 350 degrees for shiny metal or glass pans and 325 degrees for dark or non stick pans.
Beat cake mix, water, oil and eggs in large bowl on low speed for 30 second, then on medium speed for 2 minutes, scraping the bowl occasionaly.
Butter and flour 2 round cake pans, either 8" or 9" and dust with flour. Pour batter evenly into pans.
Bake 8" layers 29 - 34 minutes 9" layers 24 - 29 minutes or until toothpick inserted in center comes out clean. Cool for 10 minutes before removing from pans, then place on rack to cool completely before frosting.
While cake cools, make frosting by combining the Cool Whip, sour cream, sugar and coconut reserving 1/2 cup of the coconut to toast for garnish.
Place first layer on serving dish or cake circle before starting to frost cake. Punch holes with toothpick or skewer and drizzle half the cream of coconut over this layer. Frost this layer and top with second layer. Punch holes in this top layer as with first layer and drizzle with remaining cream of coconut. Frost top and sides and sprinkle with reserved toasted coconut.
Cake can be sliced and served immediately, but is much better if kept in refrigerator for a couple of days if you can stand to wait or at least overnight. Enjoy.