Yesterday I took off my bumper and cleaned up and painted my frame, subframe, a-arms and such; my Dixon Bros Racing prerunner bumper should be here next week sometime! Also I got new BFG's last week!
I used some ultra-flat black spray paint. Used a wire brush and acetone to clean everything up first, then taped and papered everything that I didn't want painted.
Installed switches for ABS on/off and e-fan off override.
It says it can withstand exterior well, and every other paint i've used started chipping already. I like the ultra-flat look also, which is the only way it comes. I tried a few others on the frame on the rear of my truck.