Heat oven to 325. Grease 9-inch square pan. In medium bowl, combine powdered sugar, 0.5 cup margarine and 1 TBSP whipping cream; blend well. Lightly spoon flour into measuring cup; level off. Add flour; mix until crumbly. With floured hands, press evenly in greased pan. Bake at 325 for 15 - 20 minutes, or until firm to the touch.
Meanwhile, in medium saucepan combine caramels and 1/3 cup whipping cream. Cook over low heat until caramels are melted and mixture is smooth, stirring occasionally. Remove from heat. Add pecans; stir well to coat. Immediately spoon over baked crus; spread carefully to cover.
In small saucepan over low heat, melt 1 tsp margarine and chocolate chips, stirring constantly. stir in 2 TBSP whipping cream. Drizzle over filling. Regrigerate 1 hour or until filling is firm. Cut into bars.