Personally, I've had too many issues in the past with pnp hids, ballasts, and junk eBay projectors.
If I do this I'm going with the rigid so I know it'll last.
You probably can wire it into the stock system. I have done that with my other trucks(although not Ridgid lights)I wired them into my high beam switch so I do not have to fumble for a switch when there is on coming traffic. I have a separate switch that disables them since it is illegal in my state to use them.
That being said, they
generally come with a harness and a switch.
I have a Ridgid light bar mounted to my roof.
Yes , they are over priced. Are they worth it? Depends. If you can't afford to have them fail, maybe. If you can, no. You can probably buy four cheap versions for one Ridgid.
Also, look into Vision X lights. One good thing about them , you can change them to fogs, spot beams, driving lights by purchasing different plastic lenses that snap on.