the only thing you need to watch out for is if you are going to run a much higher wattage bulb on the stock wiring. a 100watt or 150 watt bulb could lead to your stock wiring burning up due to the higher current demand of the bulbs.....this is where the upgraded haresses really shineYeah I can usually figure out mostly simple DC stuff, but just assumed the harness converted things in such a way that the bulbs wouldn't work with the factory wiring. As in the harness was REQUIRED to make the new bulbs work thus making it different from factory somehow. I just never considered that possibility but I should have I guess. I actually kinda thought the plugs wouldn't physically fit the new bulbs to be honest. The Koito harness has those boots on the plugs and I just never looked inside them to see if they matched the factory ones. Another lesson learned here on Mud. Man so many lessons here. Thanks again for this clue.