I'm sure somebody has done something similar to this, just haven't seen a thread about it. I think anybody using Stillen G3/ Takeda/ litespeed ect. style intakes can really benefit from this.
After I installed my G3's, I noticed that if you look through the front facia and up towards the crash bar where the filters are located, they are completely blocked by the foam crash absorber. Now, I know that these style intakes are dyno proven, I just felt like there could still be some improvement with airflow. Some people might say "well why not just remove the foam"... If you look on the back side of your bumper, there are some same square foam pieces glued on. Those actually rest on the foam absorber. So its probably best not to completely remove it.
Went to Lowes this morning and bought a 2ftx2ft 26guage piece of aluminum sheet metal for 24 bucks. They had smaller pieces for around 10 bucks, which would have also worked. The piece I bought was a little overkill. You could get a thicker piece as well. I only had tin snips to cut it with, so I felt the 26guage was thick enough and would be durable enough.
Cut some slots out of the foam absorber where the filters are located. Then I measured and cut the aluminum to the right sizes. Did a few bends, then I lightly sanded and spray painted, drilled a couple small holes on the crash bar and used some screws to mount ... and wallah! Now I have some deflectors to guide more air up to the filters. I'm sure this may only add 1 or 2hp, if any. Buuuut, we all know in the N/A world, that any weight you can shed, or HP you can add is a huge plus!
Not sure how much room a regular Z has in its bumper to do this, as I have a Nismo. Also, this would probably allow water to be able to reach the filters... Mine is a only nice weather, weekend warrior so that wasn't a concern for me. Just thought I would share if anybody was interested.
*The pictures of the finish product were taken upward through the fascia... if you were to just look at it on a knee straight on, you can barely see the deflectors. I know they look alittle sloppy in the pics from the angle I took them from.