So I was looking into getting a take off gt bumper from eBay cause I like the black grille surrounds, but I figured I'd give this a try first to save a few hundred. Turned out pretty nice, though I could not for the life of me get a straight edge along the bottom.
What zinc said. Pull the tape off while the dip is still wet is what I've always heard do. I had my pillars painted, I wanted them to last as long as possible, along with the bottom center of my bumper.