The kit comes complete with everything you need. Henry, NO mods to the headlight assembly. All you're doing is taking a bulb out, and putting another in. Allthough tolerable and not being able to do anything about it is, when I turn on the headlights the little screen in the gauge pod tells me to "check right/left headlight". I just hit reset. Haven't been able to find anything to stop it. RetroSolutions told me its because of the lower wattage the bulbs run at, trips the warning(like a bulb is burned out) I use thier HID lights for all my vehicles/bikes. Love 'em. Bob :banana: