Heat oven to 350. Grease and flour 9 x 13 pan. In large bowl, combine cake mix, brown sugar and peanut butter at low speed until crumbly. Reserve 1/2 cup peanut butter mixture; set aside. To remaining peanut butter mixture, add water, oil and eggs; blend at low speed until mostened. Beat 2 minutes at high speed. Stir 1/4 cup of the chocolate chips and 1/4 cup of the peanut butter chips into batter. Pour batter into greased and floured pan. In small bowl, combine reserved 1/2 cup peanut butter mixture, remaining chocolate chips and peanuts. Sprinkle over batter. Bake at 350 for 40 to 50 minutes or until toothpick inserted in center comes out clean. Immediately sprinkle with remaining peanut butter chips; gently press into top of cake. Exchanges: 3 starch, 4 fat. ----