I used an old harness from McKinney motorsports and like helghast7 said it could run the motor on a stand with a battery. There is just a couple of wires to connect and you are good to go. I read through Chris' instructions and I would have done it my self if the package deal I got on mounts and drive shaft hadn't already come with the harness. You shouldn't have to do any thing to keep your lights working just make sure that you don't cut any of those wires out when you clean up the engine bay. I took everything out of mine except the head lights, wipers, the wires for the starter and alternator. Your tail lights are on a separate terminal so there is nothing to change there.