You may not feel the difference, but when you put an aftermarket pipe on you are flowing better really making it a bit leaner and these are lean from the factory and although you have an intake air temp sensor that should richen up your mixture, they really dont do much. What you will do by programming your fuel correctly is make more power not only by supplying the extra fuel you need for the extra air velocity, but the extra fuel will cool your intake air and help to keep temperaturs down also making more power...theres alot more technical stuff along with it, but definately a good idea to run a controller man, definately !!!