I put mine in 2 years ago, ordered them from Moper4Less also! Great prices.
Anyway, I hooked mine up to a relay so that when the parking lights come on the relay is switched on also, thus taking the load off of the light switch. But I ALSO wired a small on/off switch into the ground wire of the relay, mounted it between the steering wheel and dash, so that I can flash the running lights on-off while I am running at night if I want to.
Also, for my money, the sheet metal in the roof seemed too light to hold sheet metal screws. I used the factory supplied plastic anchors and they still work great--just don't over tighten them--they seem strong enough to me. I also used a 3-M rubber-based windshield installation primer to paint the bare metal from drilling through the roof. And yes, I pulled the headliner down, but I also needed to reglue parts of it back up which had started to separate, so I needed to take it down anyway.