If you already have the PC then add the stage 1 download you will have to change the map in the PC.i have the pc3usb but i thought the stage 1 would be a plus with the pc3usb..i have the rev limmit set to 6200 but im just running 4's in the 80 and 100% colums in the ignition side of my pc map. everything else has 0's in the colums