Crush 50 wafers finely; mix with 1/4 cup sugar and margarine. Press onto bottom of 9-inch springform pan. Stand remaining wafers around edge of pan, pressing gently into crust to secure.
Beat cream cheese and remaining sugar in large bowl with mixer until blended.
Add sour cream and vanilla; mix well.
Add eggs, 1 at a time, beating on low speed after each just until blended.
Pour over crust.
Bake 45 to 50 min. or until center is almost set. Run small knife around rim of pan to loosen cake; cool before removing rim. Refrigerate cheesecake 4 hours.
Microwave caramels and milk in microwaveable bowl on HIGH 1 min. or until caramels are completely melted, stirring every 30 sec. Cool slightly.