One good rock chip and you'll have a big crack in the bumper. Urethane won't do that. Whenever you see one of those ricers with cracked spaceship ground effects hanging off... that's fiberglass.
2000 Mustang GT Steeda #0048 34k miles. 99 Cobra 4V swapped, FTBR IRS swapped, exhaust, tuned by James Gordon.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.