What all is needed for adding off-road lights?

I searched and didn't see specifics, but what all is needed for off-road lights. I'm looking at the hella 4000s and will mount them on a light bar. Do I need a harness for each light? And if I wanted a switch to turn them on I'm guessing a single switch can turn on both, and I'd need the switch I'm sure. Thanks
-mike

 

if you buy an off road light kit, it'l come with all the wiring, relay and switch

 

The 500s come with everything you need so I am guessing the 4000s do too. You might want some of that black tubing to put the wires inside though.

As for the switch you can dremmel the stock one into place or buy a OEM fog light switch from a Scion for ~$13 ( definately go for an illuminated one)

 

Cool thanks guys.