After installing my grounding kit from AT on friday and around another 600 miles of driving. I definetly can tell a difference. Here is what I found, Hesitation in engine when downshift Completely gone, Smoother ride, No difference in MPG, When Idleing almost 0 knocks and pings, No difference in brightness of lights, 0 difference in performance, smoother shifting, No difference in start up. Overall best mod for the money. I have 05 3.5, with I/E.