I installed the oem SUT tail light guards, today.
You do have to drill 2 holes, in the sheet metal, on each side.
I did so with a 5/16 rotabroach, per the instructions, and the holes are a little too big, for the screw anchors.

So, I'm not sure how well they will hold. Also, 1 of the mounting points doesn't fit flush with the sheet metal.
I also managed to scrape off some paint, near where I was drilling. I didn't make a deep enough pilot hole and the drill got away from me.

I'm no Bob Vila.
I don't know about rust. All that comes with the kit is a little tube of grease to cover the 4 holes you have to drill.
Overall, I spent $210, for the guards, and $75 for rotabroach bits, and $20 for touch up paint. I wish I'd left well enough alone.
