Preheat oven to 350
In a large bowl combine fritos, crispex, pretzels... Set aside
In a small sauce pan melt sugar, butter, and corn syrup on medium heat.
Let the mixture come to a boil and then boil for 4 minutes without stirring.
Remove the pan from the heat and pour over frito mixture, stirring to coat evenly.
Transfer mixture to a large baking pan and bake for 8 minutes
Remove to stir then bake for another 8 minutes
Transfer mixture to tin foil/wax paper
Sprinkle M&Ms on the top before the mixture cools