Combine mangos, raspberries, plums, lime juice and 6 Tbsp powdered sugar in blender. Puree until smooth. Taste and adjust sugar, as needed. Chill 1 hour, or up to 1 day. Whip heavy cream in bowl of electric mixer at medium-high speed until soft peaks form. Add 2 Tbsp powdered sugar and beat until stiff. Fold fruit puree into cream. Spoon into 4 serving bowls and top each with sprinkle of grated lime peel.