I'm sure it's not a huge deal performance wise but I found it interesting that Ford changed the design and part number for this piece between 1999 and 2001 models. Notice they removed the top set of ribs in the air duct for 2001. Iwouldnt be surprised if it helped a little bit, afterall anything is better than nothing.
Sorry man I've been tryin to get the Cobra all together. I promise I will look tomorrow afternoon for you.