banks products help

i just purchased my first diesel an 06 f-350 with a 6.0L and at 4 dollars a gallon i;m trying to get the best mpg i can....i orginally was getting 12mpg highway and i put in banks ram air and i;m gettin 13 1/4 now....i;m considering banks six gun module but my truck is still in warranty and i only have 30 g's on it and i;m getting mixed answers on the product voiding warrenties.....can anyone help me out on this.......anything will help thanks