MIX Crust Mixes, butter, sugar and 2 Tbsp. water with fork in large bowl until crumbs are well moistened. Press 1/2 of the crumbs firmly 1-1/2 inches up side of 9-inch springform pan. Press remaining crumbs firmly onto bottom of pan using measuring cup.
MICROWAVE 4 squares of the chocolate in small microwavable bowl on HIGH 2 minutes or until almost melted. Stir until chocolate is completely melted.
POUR milk into large mixer bowl. Add Filling Mixes. Beat with electric mixer on low speed until blended. Beat on medium speed 3 minutes. Beat in melted chocolate. (Filling will be thick.) Spoon into crust.
REFRIGERATE at least 1 hour or until firm. Melt remaining 2 squares chocolate just before serving. Spoon Cherry Topping onto cheesecake; drizzle with melted chocolate. Refrigerate 5 minutes to harden chocolate. Run small knife or spatula around side of pan to loosen crust; remove side of pan. Store leftover cheesecake in refrigerator.