If you're really just worried about the random stone or road trash, and light offroading (no big stumps/rocks), the thin factory plates, which offer low weight and, granted, minimal protection, would probably cover your needs... That's why I put them on mine.

Hell I've seen an Olds sedan on the Thruway that coulda used'em for that - clipped some road trash, cracked his tranny case, bleeding fluid all over the parking lot at the rest stop. We were lucky, we were only limping home with a blown radiator...