Well, my 2001 has a hard black plastic insert that starts near the shock tower, runs across the whole wheel well and curls around the shape of the front of the wheel that attaches to the front valance/fiberglass nose & undershield. There's a second one that overlaps that to keep crap out of the engine compartment itself, albeit a small one; and a corresponding one that curls behind the wheel. Clear as mud, right?
Appears to be working, though.
Hope that helps. Cheers,