Lightly grease a 9-inch pie plate. In a medium bowl combine ground peanuts, margarine or butter, and sugar. Press mixture firmly onto bottom and up sides of the prepared pie plate. Chill for 15 minutes.
Meanwhile, for filling, in a small bowl stir together coconut, corn syrup, peanut butter, and the 3 tablespoons chopped peanuts. Place ice cream in a large chilled bowl; stir ice cream just to soften. Stir in the coconut mixture just until combined. Spoon into chilled crust. If desired, sprinkle chopped chocolate pieces or peanuts over pie. Cover; freeze about 6 hours or until firm. Remove from freezer and place the pie on a warm, damp towel for a few minutes before cutting into wedges. Makes 8 servings.