Have you seen this truck? No spoiler but Camaro (obviously modified) bumpers front and rear (link below pics).
IMO you should only run a valence if you're going to run air ride. It only looks cool if it's dropped low, but if it's low it's going to scrape and get caught up on stuff (I have trouble driving my lowered mustang around in my area, and I only lowered it an inch).
http://67-72chevytrucks.com/vboard/s...547893&page=10