It won't get a lot of air because of the chin spoiler, but any little bit helps. The only caution I would have with it is that if you do an off, or start bouncing curbs it would be real easy to break it loose, and then your gifted with a black flag and or DNF.

If you have anyway to run the 3" hose near the holes in the radiator support (on the ITA CRX there were a few) you would at least have positive pressure and you could flatten the hose a little where it crosses under the front rail so you would have more gain with less risk of losing the pipe.